Commit e67def1b authored by Bernd-Christian Renner's avatar Bernd-Christian Renner
Browse files

edited intro and hardware (except customization), first round

parent 5bfc4219
......@@ -41,15 +41,15 @@ Finally, six LEDs indicate the status of the modem.
![](/images/hardware_concept/receiver.svg)
</center>
The receiver board takes the analog signal from the internal bus of the 31-pin connector and feeds it through the following analog stages:
The receiver board acquires the analog signal from the corresponding lines of the 31-pin connector and feeds it through the following analog stages:
1. Biasing and light amplification based on a low-noise, low-power JFET. The input impedance must be adjusted to the hydrophone in use.
1. Pre-amplification with an optional circuitry for a software-switchable, reduced gain in noisy environments.
1. Bandpass filter to remove noise and lightly amplify the signal. This stage relies on precise components (1%) and requires adaption of the pass band based on the used frequency band.
1. Software-controlled gain stage with 18 gain levels in steps of 2 dB.
1. Software-controlled variable gain stage with 18 gain levels in steps of 2 dB.
1. ADC
The center frequency of the 8th order bandpass can be adjusted via the 8 capacitors (CBP) and has a bandwidth of 50 kHz.
The bandpass has a bandwidth of 50 kHz. Its center frequency can be adjusted via 8 capacitors (named CBP).
Per-stage and overall gain is summarized in the following table.
| | input | pre-amp | bandpass | amplifier | total |
......@@ -68,13 +68,8 @@ Line PC0 is used to control the pre-amp gain reduction (low: full gain, high: -1
The transmitter of the ahoi modem comes in two flavors: a low-power transmitter (TX) and a high-power transmitter (TXB).
The default setup is to use TXB.
TX Bridge (TXB):
![](/images/hardware_concept/tx_bridge.svg)
TX Single (TX):
![](/images/hardware_concept/tx_single.svg)
![](/images/hardware_concept/transmitter.svg)
The structure of both variants is equal, differences are in the power supply and the power amplifier topology and ICs.
......@@ -88,10 +83,8 @@ The maximum output current is 200 mA; we recommend a peak maximum of 100 mA to p
The TX provides a +/-18 V supply via a low-power charge pump and produces an output signal of +/-17.5 V amplitude via a single op-amp.
The maximum peak output current is limited to ca. 40 mA.
Both boards host the hydrophone connector and a signal switch to connect the hydrophone either to the receiver or the sender.
The hydrophone is always connected to the receiver (via the 31-pin connector), when the transmitter is powered off.
The hydrophone is only connected to the transmitter output, if the transmitter is enabled (via line TX_EN) and line SW_TXRX is high.
Both lines are controlled by the microcontroller.
Both boards host the hydrophone connector and a signal switch to connect the hydrophone either to the transmit output circuitry or the receiver (via the lines H+ and H- on the 31-pin connector).
The hydrophone is connected to the transmit output circuitry, if the transmitter is enabled (via line TX_EN) and line SW_TXRX is logic high. Otherwise, the hydrophone is connected to the receiver (via the 31-pin connector). The behavior of both lines is software-controlled.
The transmitter is only enabled for transmission and powered off otherwise with negligable consumption. Idle consumption, when the transmitter is on but not sending, is ca. 300 mW for TX and 800 mW for TXB.
The DAC interfaces with the microcontroller via SPI (CS1). Transmit output levels are selected by software via I2C.
......@@ -100,17 +93,18 @@ The DAC interfaces with the microcontroller via SPI (CS1). Transmit output level
## Programming board
The programming board attaches to both connectors at the mainboard and contains an SWD connector and pin headers for the signal pins.
The boards is mainly used for fast programming via an ST-LINK/v2 programmer and for debugging. It can also be used for debugging, because all lines of the 31-pin connector are available via pin headers.
The boards is mainly used for fast programming via an ST-LINK/v2 programmer. It can also be used for debugging, because all lines of the 31-pin connector are available via pin headers.
For programming, a separate 12V supply is required to power the mainboard. The available supply of the programmer is not connected.
Note that you should *not* connect a 12V power supply to the programming board: this will bypass the protection circuit; use the connector on the mainboard instead.
## Debug board
Since the programming board blocks the easy access to the top side of the connected PCB, we developed a debug board.
Since the programming board blocks easy access to the top side of the connected PCB, we developed a debug board.
It has only one 31-pin connector and is mounted in a way that gives access to the entire connected PCB.
It exposes all lines of the 31-pin header, provides a standalone 3.3V supply, and several LEDs.
The 3.3V supply is required only when connecting an RX or TX(B) board for debugging or testing purposes.
You *must* disconnect this supply when attached an MB.
!!! danger "Danger"
* When you connect the debug board to an MB, you should *not* connect a 12V power supply to the programming board: this will bypass the protection circuit; use the connector on the mainboard instead! You *must* also disconnect the 3.3V supply of the debug board by removing its jumper!
* When you conect the debug board to an RX or TX(B), you have to connect the 12V supply to the debug board 12V and GND pins. Be aware that the debug board has no polarity protection!
# How to use the Hardware
This part describes how to use the hardware from the user's point of view. It explains what function the LEDs have and how to use connectors and interfaces. It also explains what additional equipment you will need to use the Modem.
## LEDs
The Mainboard has six LEDs indicating the status of the modem.
![Figure 6](/images/hardware/leds.png "Leds")
<table style="width:100%;">
<thead>
<tr>
<th colspan="4">Mainboard LEDs</th>
</tr>
<tr>
<th>LEDs</th>
<th>Color</th>
<th>Name</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>LD5</td>
<td>Orange</td>
<td>Battery Level LED</td>
<td>Displays the status of the battery voltage (see “Battery Level Code” table)</td>
<tr>
<td>LD4</td>
<td>Red</td>
<td>AGC LED</td>
<td>The LED lights up when AGC (automatic gain control) is enabled.</td>
</tr>
<tr>
<td>LD3</td>
<td>Yellow</td>
<td>SERIAL RX LED</td>
<td>The LED toggles when a UART packet from the host has been received sucessfully.</td>
</tr>
<tr>
<td>LD2</td>
<td>White</td>
<td>TX LED</td>
<td>The LED lights up during acoustic packet transmission.</td>
</tr>
<tr>
<td>LD1</td>
<td>Green</td>
<td>RX LED/td>
<td>The LED toggles upon successful reception of an acoustic packet.</td>
</tr>
<tr>
<td>LDP</td>
<td>Blue</td>
<td>Power LED</td>
<td>The LED lights up when the 3.3 V supply voltage is available.[^2]</td>
</tr>
</tbody>
</table>
[^2] The mainboard has a hardware build option to switch off the LED during sleep mode. This option is currently not support by the release firmware.
<table style="width:100%; margin-bottom:25px;">
<thead>
<tr>
<th colspan="2">Battery Level Code</th>
</tr>
<tr>
<th>Code</th>
<th>Status</th>
</tr>
</thead>
<tbody>
<tr>
<td><img src="/images/hardware/leds_s5.png" alt="Leds status excellent"></td>
<td>Excellent, 75-100%</td>
</tr>
<tr>
<td><img src="/images/hardware/leds_s4.png" alt="Leds status good"></td>
<td>Good, 50-75%</td>
</tr>
<tr>
<td><img src="/images/hardware/leds_s3.png" alt="Leds status low"></td>
<td>Low, 25-50%</td>
</tr>
<tr>
<td><img src="/images/hardware/leds_s2.png" alt="Leds status critical"></td>
<td>Critical, 0-25% </td>
</tr>
<tr>
<td><img src="/images/hardware/leds_s1.png" alt="Leds status too high"></td>
<td>Too high</td>
</tr>
</tbody>
</table>
!!! info "Info"
The indicator levels are rough estimates based on a 3S LiPo battery with 12.4 V nominal rating.
See [Customising the Firmware](/tutorial_firmware/#fw_batlevels) for details.
## Connectors
### Mainboard MB
The mainboard is the main interfacing part of the ahoi acoustic modem.
It comprises two pin header connectors, one for power supply (C1) and one for external I/O (C2).
![Figure 5](/images/hardware/mb_connectors.png "MB connectors")
##### Power Supply
<table style="width:100%; margin-bottom:25px;">
<thead>
<tr>
<th colspan="3">C1: Supply (Pin header 2.54mm)</th>
</tr>
<tr>
<th>PIN</th>
<th>Signal name</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>1</td>
<td>GND</td>
<td>Power ground</td>
<tr>
<td>2</td>
<td>Vin</td>
<td>Positive power (12V or 3S battery)</td>
</tr>
</tbody>
</table>
!!! info "Info"
Connector (C1) powers the modem in all operation modes (including firmware updating / programming). This power connector is the only one that is reverse voltage protected.
!!! danger "Input voltage"
The modem accepts any **input voltage from 10 to 13 V**. Exceeding this range may cause permanent damage to the device.
#### External I/O
<table style="width:100%;">
<thead>
<tr>
<th colspan="4">C2: External I/O (Pin header 2.54mm)</th>
</tr>
<tr>
<th>PIN</th>
<th>Signal name</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>1</td>
<td>EN / WUP</td>
<td>input</td>
<td>Modem wake-up from sleep via rising edge[^1]</td>
<tr>
<td>2</td>
<td>PKT</td>
<td>output</td>
<td>Packet available indicator. This pin is logic high, while a packet is available on the modem[^1]</td>
</tr>
<tr>
<td>3</td>
<td>NC</td>
<td></td>
<td>Not connected</td>
</tr>
<tr>
<td>4</td>
<td>RXD</td>
<td>output</td>
<td>UART isolated receive data (receive line of host)</td>
</tr>
<tr>
<td>5</td>
<td>TXD</td>
<td>input</td>
<td>UART isolated transmit data (transmit line of host)</td>
</tr>
<tr>
<td>6</td>
<td>VCC</td>
<td>power</td>
<td>UART isolated Power</td>
</tr>
<tr>
<td>7</td>
<td>NC</td>
<td></td>
<td>Not connected</td>
</tr>
<tr>
<td>8</td>
<td>GND</td>
<td>power</td>
<td>UART isolated Ground</td>
</tr>
</tbody>
</table>
[^1] For future use, currently not supported by release firmware.
!!! info "Info"
The external I/O connector is mainly intended for serial communication between host and modem. All lines are isolated, so that external power is required. We recommend to use 3.3 V input voltage and logic levels; however, the isolators have a maximum rating of 5.5V.
### Transmitter TXB / TX
![Figure 5](/images/hardware/tx_connectors.png "TXB/TX connectors")
<table style="width:100%; margin-bottom:25px;">
<thead>
<tr>
<th colspan="3">C3: Hydrophone</th>
</tr>
<tr>
<th>PIN</th>
<th>Signal name</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>1</td>
<td>H+</td>
<td>Hydrophone positive</td>
<tr>
<td>2</td>
<td>Shielding</td>
<td>Hydrophone shielding (2-wire)</td>
</tr>
<tr>
<td>3</td>
<td>H-</td>
<td>Hydrophone negative (2-wire) or shield (1-wire)</td>
</tr>
</tbody>
</table>
!!! warning "Info"
The hydrophone **must** be connected to the TX board. If your hydrophone has a separate shield and two connection wires, connect them as indicated on the table. If your hydrophone only has a single wire and shield, connect the shield to H- and do not connect the shielding on the TX board.
## Accessories
In this section, we list and explained the additional equipment you need in addition to the three PCBs.
### Hydrophone
![Figure 7](/images/accessories/hydrophone.png "Hydrophone")
### Power supply
The modem is designed to work with 3-cell (3S) Lithium-Polymer-Accumulator (LiPo) batteries. If you use one with a JST BEC connector, you can connect this battery directly to the supply pin header (C1) on the mainboard.
![Figure 8](/images/accessories/batterie.png "3S LiPo Battery")
Alternatively, you can also use a 12V power supply, like a bench power supply. It may be convenient to build an adapter cable from 4mm Banana to 2.54mm pin header.
![Figure 9](/images/accessories/banana.png "12V Banana")
!!! warning "Unfused"
The modem has no integrated fuse. Be careful when the batterie is connected. Short cuts will damage the board.
Add a fuse or use the current limit at the power supply, to avoid bigger damages.
### Serial Communication
To communicate with the modem, a USB-to-serial adapter is required. The external I/O connector (C2) is designed to accept a TTL-232R-3V3 adapter with 6-pin female connector directly.
![Figure 10](/images/accessories/usb-uart.png "USB-UART")
# Test the hardware
# Testing the Hardware
## Testing requirements
If you build the hardware yourself, some tests are necessary to check if the final board works as intended.
The tests can be done without knowing much of the hardware details. For a better understanding take a look at the hardware concept, though.
Particularly when building the hardware yourself, we recommend a test procedure that we established for our own builds.
These tests can be done without knowing much of the hardware details. For a better understanding, take a look at the hardware concept, though.
If you use a professionally assembled board, you can skip many steps in the test, as soldering errors are not so common as on a hand soldered board.
If you use professionally assembled boards, you can skip many steps in the test, as soldering errors are relatively uncommon as compared to hand soldering.
For executing the tests, you need the following tools and should know how to use them:
For executing the tests, you need the following tools and should be experienced in their use:
- Power supply (12V with current limitation)
- Multimeter
......@@ -27,8 +27,9 @@ In the following, we describe standard test procedures for each board. The board
### Manual test
<center>
![](/images/hardware_check/testpoints/debug_board_txb.png)
</center>
0. For a test without a connected mainboard, an externally generated signal must be used. The DAC has to be disconnected by removing resistor RS1.
......@@ -36,12 +37,12 @@ In the following, we describe standard test procedures for each board. The board
!!! danger "Danger"
Failure to remove RS1 in the following test procedure will apply a reverse voltage to the DAC and may cause permanent damage.
1. Use a testboard (AHOI-TST) to generate the logic-level voltage and to enable the TXB board. On the testboard, set the 3.3V Jumper (green). Connect 12VDC (red) and GND (black) to a power supply. Attach the testboard to the TXB board.
1. Use a testboard (AHOI-TST) to generate the logic-level voltage and to enable the TXB board. On the testboard, connect the 3.3V Jumper (green). Connect 12VDC (red) and GND (black) to a power supply. Attach the testboard to the TXB board.
Leave the blue and pink connection open, they will be connected later.
The power consumption (at 12V) should be around 4.5 mA.
2. Connect TXEN to 3.3V (pink). Power consumption should increase to around 7080 mA. (7-8 mA, if only the DCDC supplies without amplifiers are soldered on the TXB board).
2. Connect TXEN to 3.3V (pink). Power consumption should increase to around 7080mA (7-8mA, if only the DCDC supplies without amplifiers are soldered on the TXB board).
You should see a stable and symmetrical voltage around +- 22VDC at the testpoints V+ and V-, respectively. Depending on the resistor tolerances, a few hundred millivolts of error are expected and acceptable.
!!! danger "Voltage"
......@@ -58,24 +59,28 @@ In the following, we describe standard test procedures for each board. The board
![](/images/hardware_check/measurements/txb_1.png "Figure 2: Signals (green: H-, yellow: H+, blue: input signal, red: gain control)")
The green curve is the negative hydrophone output (H-), the yellow one the positive output (H+). The input signal is blue, and the signal after the gain stage is pink. In our test, we used a frequency of 60 kHz.
The green curve is the inverted hydrophone output (H-), the yellow one the non-inverted output (H+). The input signal is blue, and the signal after the gain stage is pink. In our test, we used a frequency of 60kHz.
Please note that the gain stage will default to a gain of 0.5; therefore, the peak-to-peak amplitude at the transmitter board outputs H+ and H- will be half of the maximum.
Please note that the gain stage will default to a gain of 0.5; therefore, the peak-to-peak amplitude will be half of the maximum
If you experience different voltages at the transmitter output, we suggest to check the signal path at the following intermediate test points:
* The peak-to-peak amplitude at the gain stage should be 1.5V with an offset of 1.5V
* The peak-to-peak amplitudes of the output signals (H+ and H-) should be 20V with a 0V offset and a 180° phase shift.
* The peak-to-peak amplitude at the low-pass filter outputs L1 and L2 should be 3V with an offset of 1.5V.
* The peak-to-peak amplitude at the gain stage G should be 1.5V with an offset of 1.5V.
* The peak-to-peak amplitudes of the power amplifier stage (A and B) should be 20V with a 0V offset and a 180° phase shift.
* The peak-to-peak amplitudes of the output signals (H+ and H-) should be the same as A and B.
### Simple test with mainboard
### Test with Mainboard
For a test with the mainboard you need a working MoSh (see setup PyLib) and a USB to UART Converter (3.3V logic-level).
For a test with the mainboard, you need a working MoSh (see setup PyLib) and a USB to UART converter (3.3V logic-level).
The DAC has to be connected to the amplifier, so the resistor RS1 must be soldered (if not already).
Input to the shell is marked with `>>`.
1. Attach the TXB board to the mainboard. Connect a power supply (12V) to the supply pins of the mainboard (12V, GND).
Connect the mainboard to your PC via the USB2UART converter and the hydrophone output of the TXB board to an oscilloscope.
Connect the mainboard to your PC via the USB to UART converter and the hydrophone output of the TXB board to an oscilloscope.
The oscilloscope should be configured as follows:
|Parameter | Setting |
......@@ -102,8 +107,8 @@ RX@1603887394.201 00 00 84 00 00 01 00 ()
>> txgain 0
```
5. Send the command to generate a testsweep. The first parameter "false" disables the compensation for a specific hydrophone
transmission curve. The second parameter is the gap between the frequencies in symbols.
5. Send the command to generate a test sweep. The first parameter "false" disables the compensation for a specific hydrophone
transmission curve. The second parameter is the gap between the frequencies as number of symbols.
```
>> testsweep false 1
......@@ -113,7 +118,8 @@ The output waveforms should look like the following pictures (left). The amplitu
Each bar is a specific transmission frequency and should have an identical amplitude (like the left picture).
The right picture shows the signal with active gain compensation and no delay between each frequency. This makes it harder to detect a fault in the transmission.
The right picture shows the signal with active hydrophone
transmission curve compensation and no delay between each frequency. This makes it harder to detect a fault in the transmission.
Compensation off | Compensation on
......@@ -126,7 +132,7 @@ Compensation off | Compensation on
>> testsweep false 1
```
The waveform should look like previous, but the amplitude has to be reduced by 6dB (50%).
The waveform should look like the previous one, but the amplitude should be reduced by 6dB (50%).
### Testpoints
......@@ -157,14 +163,14 @@ Top | Bottom
| 14 | B | Output signal | [See TP A] |
## TX
## Transmitter (TX)
### Test
!!! info "Info"
The TX Board can be tested similar to the TXB board, so only the differences are described in the following.
The resistor RS1 connects the DAC to the amplifier stage. For testing the amplifier stage, resistor RS0 has to be removed and an external signal generator can be connected to the input pad.
The resistor RS1 connects the DAC to the amplifier stage. For testing the amplifier stage, resistor RS1 has to be removed and an external signal generator can be connected to the input pad.
The TX board is more sensitive than the TXB board and can easily become damaged during tests. Therefore, it is recommended to assemble the whole board, check for shorts and test it directly with the mainboard and RS1 soldered.
The TX boards only use the H+ signal of the hydrophone. H- is tied to ground. The peak-to-peak amplitude of the output signal should be around 32V.
......@@ -189,7 +195,7 @@ The TX boards only use the H+ signal of the hydrophone. H- is tied to ground. Th
## RX
## Receiver (RX)
The receiver circuits are designed to amplify extremely small signals. For the test, it is necessary to attenuate the input signals before they get inserted into the input pins of the RX circuit.
......@@ -197,14 +203,15 @@ To do this, you have to build an attenuator using a simple 1,000x voltage divide
For the connection to the test board use shielded wire, where the shield is only connected to the shield connector on the test board.
The connection to the signal generator can be left unshielded due to the higher signal voltages and to prevent ground loops.
<center>
![](/images/hardware_check/drawing/rx_attenuator.svg)
</center>
If required: Connect the ground of the signal generator to the ground of the 12V supply near the connector on the testboard. If the ground of the signal is generator is internally tied to the ground of the oscilloscope, we strongly advise to not connect the signal generator to prevent ground loops.
If required: Connect the ground of the signal generator to the ground of the 12V supply near the connector on the testboard. If the ground of the signal generator is internally tied to the ground of the oscilloscope, we strongly advise to not connect the signal generator ground to prevent ground loops.
!!! danger "Only AC input signals"
The input stage (JFET) will be damaged if a DC signal is applied. The generated signal must only have an AC part.
The input stage (JFET) will be damaged if a DC signal is applied. The generated signal must only have AC components.
......@@ -213,8 +220,8 @@ If required: Connect the ground of the signal generator to the ground of the 12V
A manual test of the receiver board can be done by applying a signal at the hydrophone input pins and measure the amplified signal at the ADC input pins. To get access to the hydrophone pins use the ahoi test board.
1. Attach the ahoi test board to the RX board. Connect the 12V supply pins to a 12V power supply. Make sure that 3.3V supply jumper is connected.
The current should be around 4.6mA (by DCDC on testboard).
1. Attach the ahoi test board to the RX board. Connect the 12V supply pins to a 12V power supply. Make sure that the 3.3V supply jumper is connected.
The current should be around 4.6mA (caused by the DCDC converter on the testboard).
2. Connect RX_EN to 3.3V on the test board.
The current should increase to ca. 15mA.
......@@ -231,13 +238,11 @@ A manual test of the receiver board can be done by applying a signal at the hydr
### Automatic test
The receiver board can be tested with an automated test setup (shown in the following picture). It can measure the frequency response of the bandpass over the complete frequency range.
So you can see if the analog filter is working correctly (and also if the rest is working).
The receiver board can be tested with an automated test procedure and setup (shown in the following picture). This procedure will measure the frequency response of the bandpass across a wide frequency range and lets you see if the analog filter chain and gain adjustment is working correctly.
You have to attach a mainboard with a USB to UART converter to the RX board.
For the measurements, a Tiepie USB-oscilloscope is used (HandyScope HS5).
The generator output is used as the signal source connected to input 1 (to check if the generator signal is correct) and the attenuator circuit.
The generator output is used as the signal source connected to input 1 of the oscilloscope (to check if the generator signal is correct) and the attenuator circuit.
The attenuated signal is connected to the RX board via the programming board (figure 8). Use the pins at the red marking.
Connect the power supply to the 12V connector on the mainboard.
......@@ -253,11 +258,11 @@ Leave the other ground connectors of the Tiepie unconnected.
* Only connect the ground of the second HS5 channel to ground, leave the grounds of the signal generator and channel 1 floating
* Use a 10,000x voltage divider (we suggest 100k and 10 Ohm) - check the values of the voltage divider resistors
After you have set up the hardware, it is necessary to setup the software.
After you have set up the hardware, it is necessary to set up the software.
The required scripts can be found in the ahoi-tools repository (see [Resources](/resources)). Follow the instructions in the included INSTALL file (pcb-test
tiepie/). Also a working modem PyLib is nessesary. If it's not set up already, [do it now](/setup_pylib).
tiepie/). A working modem PyLib is also neccesary. If it's not set up already, [do it now](/setup_pylib).
Afterwards, start the automatic measurement script:
```
......@@ -304,8 +309,8 @@ gain 18: mean = 2.492V, std = 134.4mV
If everything is correct, the reported values should be similar as above. In particular, the mean values should be close to 2.5V (with an error of at most 10mV). The std values should approximately quadruple (except for the first entry), and they should be within 2x the sample values above.
The created plot shows the gain of the four gain levels over the frequency.
The bandpass region is marked and between the green vertical bars. The transmission outside this window is not important, but it may indicate that something is not working correct.
The created plot shows the gain of four gain levels over a frequency range.
The bandpass region is marked by two green vertical bars. The transmission outside this window is not important, but it may indicate that something is not working correct.
The red horizontal bars are the limits for the lowest and highest gain setting. The red curve should be at the upper level, the blue line should be at the lower red line.
The other curves (green and yellow) should be in between.
......@@ -313,13 +318,17 @@ The other curves (green and yellow) should be in between.
![](/images/hw_build/measurements/rx.jpg)
#### Extended measurements
If you want to measure more gain steps it is possible. Use the command:
To speed up the testing procedure, the test script only measures the frequency response of the receiver for a small number of gain stages. It is, however, possible to measure additional gain steps by providing the requested gain stages to the script with the option `-l`.
Example:
```
>> python3 recRXGain.py <id> -l 0:1:18
```
This will measure the gain in steps from setting 0 to 18 with a step of 1. Other configurations are also possible.
The evaluation script will only use 4 fixed gin configurations, the additional ones are ignored. You can find the recorded data in the folder “pcb-test/tiepie/data/rx-id” as matlab files.
This will measure the frequency response (gain) from setting 0 to 18 with a step size of 1. Other configurations are also possible. Please refer to the manual of the test script.
For further analyze, we would like to point out that the recorded data will be stored in the folder “pcb-test/tiepie/data/rx-id” as Matlab files.
### Testpoints
......@@ -333,12 +342,12 @@ The evaluation script will only use 4 fixed gin configurations, the additional o
|2 | PRE2 | Signal after pre-amplifier 2 (opamp) | PRE * 60 |
|3 | VREF | Reference voltage for op-amps | VANA / 2 => 2.5V |
|4 | VDD | Supply voltage | ~5.25V when RXEN high |
|5 | LP | Signal after 8th order bandpass filter | PRE2 * 1.5 (42kHz) |
|7 | AMP | | LP * Gain (Poti) [1] |
|5 | LP | Signal after 8th order bandpass filter | PRE2 * 1.5 (42kHz) |
|7 | AMP | | LP * Gain (Poti) [^1] |
|6 | SIG | ADC input (AMP plus buffer RC) | AMP |
|8 | VANA | Switched supply voltage | 5.0V when VDD power good |
[1] Gain in unconfigured state: x3
[^1]: Gain in unconfigured state: x3
If the bandpass filter is not working correctly, further points are available for testing:
......@@ -353,11 +362,11 @@ If the bandpass filter is not working correctly, further points are available fo
|TB4 / LP | ca. 1 (+5%) | TB3 |
## MB
## Mainboard (MB)
### Test
The mainboard has no special test points. Due to the structure, there is no signal chain and therefore each circuit part works independently of each other. If some part of the board is not working correctly, you can use the schematic to check the components for their function.
The mainboard has no dedicated test points. All circuit parts work independently of each other. If some part of the board is not working correctly, you can use the schematic to check the components for their function.
One central part of the board is the power supply circuit. It is used to create the 3.3V from the input voltage, distribute it to the components on the mainboard and - via the connectors - to the daughter boards (RX, TX/TXB). If this is not working correctly,
it can damage many components and should be tested before the following components are soldered: microcontroller, EEPROM, isolators.
......
# How to use the Hardware
This part describes how to use the hardware from the user's point of view. It explains what function the LEDs have and how to use connectors and interfaces. It also explains what additional equipment you will need to use the modem.
## LEDs
The mainboard (MB) has six LEDs indicating the status of the modem.
![Mainboard LEDs](/images/hardware/leds.png "Leds")
| LED | Color | Function | Description |
| | | | |
| LD5 | Orange | Battery&nbsp;level | Displays the status of the battery (see “Battery Level Code” table) |
| LD4 | Red | AGC&nbsp;on | Lit when AGC (automatic gain control) is enabled. |
| LD3 | Yellow | Serial&nbsp;RX | Lit when AGC (automatic gain control) is enabled. |
| LD2 | White | Acoustic&nbsp;TX | Toggles when a UART packet from the host has been received successfully. |
| LD1 | Green | Acoustic&nbsp;RX | Toggles upon successful reception of an acoustic packet. |
| LDP | Blue | Power&nbsp;on | Lit when the 3.3V supply voltage is available[^1]. |
[^1]: The mainboard has a hardware build option to switch off the LED during sleep mode. This mode will become available in a future firmware release.
The battery-level LED has the following blink pattern to indicate the battery status.
| Blink Code | Status |
| -:- | :-- |
| ![](/images/hardware/leds_s5.png) | Excellent, 75-100% |
| ![](/images/hardware/leds_s4.png) | Good, 50-75% |
| ![](/images/hardware/leds_s3.png) | Low, 25-50% |
| ![](/images/hardware/leds_s2.png) | Critical, 0-25% |
| ![](/images/hardware/leds_s1.png) | Too high |
!!! info "Info"
The indicator levels are rough estimates based on a 3S LiPo battery with 12.4 V nominal rating.
See [Customizing the Firmware](/tutorial_firmware/#fw_batlevels) for details.
## Connectors