PV198 - SPI II
One-chip Controllers
Daniel Dlhopolček, Marek Vrbka, Jan Koniarik, Oldřich Pecák, Tomáš
Rohlínek, Ján Labuda, Jan Horáček, Matúš Škvarla
Faculty of Informatics, Masaryk University
9/2023
Introduction
Intro
Switch the branch to Week_09!
Discussion of HW8
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Task
Context
In some cases it is necessary to serve not to rule.
Goal is to implement SPI slave functionality:
Instead of driving SPI bus, react to master device.
Data should be prepared in advance, goal is to react to requests:
You will be provided an interface with 3 features in blocking mode
and you will implement these features non-blocking mode.
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Task
Goal
SPI slave will be able to react to two types of messages, type of
message is deduced from first byte:
1. WRITE: print all subsequent bytes to UART.
2. READ: report latest measured ADC value.
First byte in slave’s reply is a counter - number of correct
communications completed.
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Task
Template
Template uses a non-blocking polling method:
1. DSPI_SlaveUserCallback
This function is called after a transfer is finished (similar to
interrupt).
2. while (!isTransferCompleted)
This while loop keeps you blocked, remove it with caution.
3. The rest of implementation is up to you.
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Task
Wiring
Rpi pico FRDM-K66P
GND GND
GP2 PTD1
GP3 PTD3
GP4 PTD2
GP5 PTD0
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Task
Counter
Counter header:
1. Every time you finish either WRITE or READ operation, count
increases.
2. Count is represented by 8bit unsigned number. It can overflow.
3. Repeated comunication with neither READ nor WRITE does not
affect the counter.
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Task
READ
Read ADC value:
1. Read values from ADC1 SE_13.
2. Read command is identified by value 0x55.
3. Expected ADC value is Big Endian, 12bit long.
4. Prepare ADC value in advance.
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Task
WRITE
Transmit 16 recieved bytes recived by SPI to UART:
1. Configure PTB11 as UART3_TX.
2. Write command is identified by value 0xCC.
3. You will recieve a chunk of 16 bytes. After you get them all, print
your data to UART.
4. Beware: blocking transmit on UART might give you problems in
callback.
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Task
Homework
Finish assignment for the lesson.
Scope of lesson is deliberately larger.
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Task
Bonus
Recieve chunks of 3 bytes.
1. Configure PTB10 as UART3_RX.
2. Write command is initialized by value 0x37.
3. You will be asked to return 3 bytes stored, that you recieved by
UART3_RX.
4. If there were no data stored, return random data but do not
increment counter.
5. Make internal memory 64messages long. If more massages
recieved, overwrite the oldest one.
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