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Lup Yuen Lee 李立源

Raspberry Pi Pico also uses the old SPI terms

raspberrypi.github.io/pico-sdk

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Lup Yuen Lee 李立源

SPI Registers are remarkably similar to I2C Registers ... So I can reuse my I2C code for SPI 🤔

github.com/bouffalolab/bl_docs

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Lup Yuen Lee 李立源

SPI Register Fields look similar to I2C too

github.com/bouffalolab/bl_docs

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Lup Yuen Lee 李立源

Yep SPI is copy pasta from I2C ... Even the Register Address. Very nice! 👍

github.com/bouffalolab/bl_docs

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Lup Yuen Lee 李立源

We'll let talk simple SPI to BME280 first ... Before talking seriously to ST7789

cdn.sparkfun.com/assets/learn_

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Lup Yuen Lee 李立源

SPI DMA ... Lets you specify a Linked List of Transmit / Receive operations ... That will be executed by the DMA Controller

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

SPI DMA uses simple Interrupt Handlers .... Simpler than I2C! Let's experiment with SPI DMA on BME280

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

SPI DMA is used by AliOS VFS file system ... Which is bundled with the BL602 IoT SDK

pine64.github.io/bl602-docs/Co

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Lup Yuen Lee 李立源

"AOS" means "AliOS" ... So IoT SDK is actually built on AliOS! But no worries ... I can port the BL602 HAL to ... Without AliOS 😉

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

But if AliOS is really a complete Embedded Operating System ... Why does IoT SDK still need FreeRTOS? 🤔

github.com/alibaba/AliOS-Thing

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Lup Yuen Lee 李立源

SPI Functions are the same as AliOS ... Time to practice my Chinese reading skills

help.aliyun.com/document_detai

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Lup Yuen Lee 李立源

...But SPI HAL doesn't implement all AliOS SPI Functions 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Init the SPI Port ... Looks easy

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Nope it's a trap! Should call "vfs_spi_init_fullname" to init the SPI port

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Another trap! "vfs_spi_init_fullname" doesn't return the SPI Device ... It passes the SPI Device to AliOS! Let's create our own function to init the SPI Port without AliOS 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Init SPI Port ... No more traps!

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

SPI Data Transfer needs a "void *" parameter ... Which is cast to an "spi_ioc_transfer_t" ... That belongs to AliOS 😭

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Saturday night with my lovelies ... @PINE64 and BME280 ... Now connecting SPI

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Lup Yuen Lee 李立源

Hope SPI is wired correctly to 🤔

1
Lup Yuen Lee 李立源

Good Sunday Morning @PINE64 ... And on SPI! Yep this looks right 👍

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

SPI Transmit and Receive ... Hope this works 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Our SPI program hangs when doing data transfer 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

SPI DMA Transfer is hanging inside "hal_spi_dma_trans" ... According to the debug log 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

"hal_spi_dma_trans" hangs while doing SPI DMA transfer because it's waiting for a FreeRTOS Event Group ... Which is supposed to be signalled by the DMA Interrupt Handler. Let's comment out the waiting and see what happens...

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Commented out the waiting for SPI DMA ... Yep no more hanging ... But no SPI Data received. Interrupt Counters show that DMA Interrupts weren't triggered.

The plot thickens ... Just like my chicken soup 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

These 2 SPI Functions are begging me to call them ... Phew this SPI HAL is confusing 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

SPI Transmit seems OK but not SPI Receive ... After calling "hal_spi_init" 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

SPI DMA uses a Linked List of DMA requests ... Let's dump the DMA Linked List and verify the SPI Transmit and Receive requests

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Aha SPI DMA is now Transmitting AND Receiving! The SPI Mode was incorrect ... Got confused between the AliOS docs and the BL602 implementation 🙁

Received SPI Data is garbage though 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

...And why did the WiFi Light (top LED) switch on? 🤔

1
Lup Yuen Lee 李立源

Let's test SPI with

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Lup Yuen Lee 李立源

SPI tests OK with

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Contemplating my Life Choices ... Erm whether I should use to sniff the SPI Bus 🤔

dangerousprototypes.com/docs/S

1
Lup Yuen Lee 李立源

Potential Bug in SPI HAL

github.com/bouffalolab/bl_iot_

1
Lup Yuen Lee 李立源

...Or use a real Logic Analyser ... To debug the SPI Bus? 🤔

seeedstudio.com/LA2016-Logic-A

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Lup Yuen Lee 李立源

and recommended SPI Pins ... Let's try them

wiki.pine64.org/wiki/Nutcracke

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Lup Yuen Lee 李立源

Testing the Recommended SPI Pins for @ThePine64

wiki.pine64.org/wiki/Nutcracke

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Lup Yuen Lee 李立源

Nope Recommended SPI Pins for also don't work

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

...But now we get pretty Blue and Red Lights on ! 🤩 Time to do the SPI Protocol Analyser ... My first time ever!

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源
Follow

Test the Logic Analyser with ... Before connecting to and BME280

qdkingst.com/en/download

· · Tusky · 1 · 1 · 1
Lup Yuen Lee 李立源

Logic Analyser connected to and ... Hope this works 🤔

qdkingst.com/en/download

1
Lup Yuen Lee 李立源

Logic Analyser captures SPI Data between and ... So cool! 🤩 Now to capture + BME280 and compare

qdkingst.com/en/download

1
Lup Yuen Lee 李立源

@ThePine64 connected to BME280 and LA2016 Logic Analyser ... Let's sniff the SPI Bus and find out what's wrong!

1
Lup Yuen Lee 李立源

SPI Data Pins seem to be flipped ... Based on SPI data sniffed by Logic Analyser 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Let's try 2 SPI Transfers instead of 1 ... First SPI Transfer transmits Register ID ... Second SPI Transfer receives the result from BME280

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Nope still receiving garbage from BME280 ... Let's do the Logic Analyser!

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

LA2016 Logic Analyser comes in this beautiful inspirational box ... "Embedded Development Kit: Innovative concept, win-win cooperation"

1
Lup Yuen Lee 李立源

Ugh is disrupting the two SPI Transfers ... By setting the Chip Enable Pin high ... Let's control Chip Enable Pin ourselves with GPIO

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Thankfully SPI HAL lets us use GPIO to control the Chip Select Pin ... But we have already configured the pin for SPI Function ... Will this conflict with the GPIO Function? 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Nope HAL can't control Chip Select Pin by ... Because it has already configured the pin for SPI Port earlier ... Let's control the pin ourselves 👋

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Here's how we control Chip Select Pin ourselves ... Using plain old BL602 GPIO

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Why does BME280 return different results ... For Bus Pirate vs ? 🤔

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Lup Yuen Lee 李立源

Unsolved Mysteries ... 1️⃣ Why are the SPI Data Pins flipped? 2️⃣ Why does Pin 0 light up the WiFi LED? 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Getting desperate with SPI ... Let's try to dump all BME280 Registers ... And see what works

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

SPI works OK yay @PINE64 ! Had to change SPI Phase from 0 to 1 ... Which doesn't sound logical 🤔

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Phase 1 ... Looks suspiciously like Phase 0 🤔

1
Lup Yuen Lee 李立源

@ThePine64 tested OK with over ... Here's the wiring that doesn't light up the WiFi LED 💡

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

@PINE64 with Acupuncture ... Erm Logic Analyser

1
Lup Yuen Lee 李立源

... Now writing about the 4 fixes I made ... 1️⃣ SPI Data Pins are flipped 2️⃣ SPI Phase should be 1 (though it behaves like 0) 3️⃣ Doing SPI Chip Select ourselves 4️⃣ Pin 0 switches on WiFi LED. Thanks for bearing with this long thread on @PINE64 🙏

lupyuen.github.io/articles/spi

1
jeancf

@lupyuen MISO MOSI behavior is defined by the clock polarity and phase parameters. You probably have them set differently in both cases.

analog.com/media/en/analog-dia

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Lup Yuen Lee 李立源

@jeancf Thanks lemme go check...

0
A Ton of ₳da

@lupyuen

So I can get into your system wirelessly {;-)

0
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