Where do I find details on using the M4F cores on the Azure Sphere?

Question

During the recent webinar, I'm sure I saw an email address where you could get more information on working with the M4F cores on the MT3620. I think it was an avnet.com address, but now I can't find it anywhere. Does anyone know where I can find it - or any other sources of information?

I'm already aware of the samples in the 19.05 SDK release, but it would be good to know more - specifically what to expect might be on the roadmap.

rscasny · Accepted Answer

David,

Not 100% sure this is what you were looking for....

But on this page:

https://docs.microsoft.com/en-us/azure-sphere/hardware/mt3620-product-status

I found this note:

For details about programming the M4 cores on the MT3620, request the MT3620 M4 Datasheet from Avnet by emailing Azure.Sphere@avnet.com.

Fred27 · Answer

I got a helpful email today From Avnet who are apparently are " working with MediaTek to see if they can provide a non-NDA version of the datasheet".

peterfenn · Answer

I can relate to your frustration regarding key Mediatek documents only being accessible with a signed NDA agreement Right now the technical document you have access to without an NDA is this one: MediaTek MT3620 Product Brief Nov2018 (23 pages) https://www.mediatek.com/products/azureSphere/mt3620 Access to the full unabridged datasheet and programmers guide requires NDA agreement - MT3620 M4 Datasheet v2019-07-02_v1.3.pdf (389 pages) - MT3620 M4 Programmers Guide.pdf (281 pages) This situation is however being addressed, my understanding is that Mediatek will soon be providing two shortened non-NDA documents: MT3620 Datasheet v0.78.pdf (63 pages) - Available by end of August (no NDA required) MT3620 M4 Functional Specification - Based on the above MT3620 M4 Programmers Guide and will include example code (no NDA required) -Peter

peterfenn · Answer

Georgi I am requesting on your behalf the mentioned excel MT3620 spreadsheet (host_uart_baud_rate.xls) for calculating UART baud rate settings, but it will likely take a couple of hours before I receive this from Mediatek. -Peter

wizio · Answer

SysTick will measure soon... I don`t want NDA for now UART tested with 4800, 9600, 19200 and 115200 int UART_SetFormat( uint32_t BASE, uint32_t baudrate, uint16_t databit, uint16_t parity, uint16_t stopbit) { #define UART_CLOCK_FREQ 26000000 uint16_t control_word; uint32_t data, uart_lcr, high_speed_div, sample_count, sample_point, fraction; uint16_t fraction_L_mapping[] = { 0x00 , 0x10 , 0x44 , 0x92 , 0x29 , 0xaa , 0xb6 , 0xdb , 0xad , 0xff , 0xff }; uint16_t fraction_M_mapping[] = { 0x00 , 0x00 , 0x00 , 0x00 , 0x01 , 0x01 , 0x01 , 0x01 , 0x01 , 0x01 , 0x03 }; // 100, 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600 WriteReg32(BASE, UART_RATE_STEP, 0x3 ); // based on sampe_count * baud_pulse, baud_rate = system clock frequency / sampe_count /* DLAB start */ uart_lcr = ReadReg32(BASE, UART_LCR); WriteReg32(BASE, UART_LCR, (uart_lcr | UART_LCR_DLAB)); data = UART_CLOCK_FREQ / baudrate; high_speed_div = (data >> 8 ) + 1 ; // divided by 256 { sample_count = data / high_speed_div - 1 ; if (sample_count == 3 ) { sample_point = 0 ; } else { sample_point = sample_count / 2 - 1 ; } if (!(data >= 4 )) return - 1 ; } fraction = (UART_CLOCK_FREQ * 10 / baudrate / data - (sample_count + 1 ) * 10 ) % 10 ; WriteReg32(BASE, UART_DLL, (high_speed_div & 0x00ff )); WriteReg32(BASE, UART_DLH, ((high_speed_div >> 8 ) & 0x00ff )); WriteReg32(BASE, UART_STEP_COUNT, sample_count); WriteReg32(BASE, UART_SAMPLE_COUNT, sample_point); WriteReg32(BASE, UART_FRACDIV_M, fraction_M_mapping[fraction]); WriteReg32(BASE, UART_FRACDIV_L, fraction_L_mapping[fraction]); WriteReg32(BASE, UART_LCR, uart_lcr); /* DLAB end */ WriteReg32(BASE, UART_FCR, 0x77 ); control_word = ReadReg32(BASE, UART_LCR); /* DLAB start */ control_word &= ~UART_DATA_MASK; control_word |= databit; control_word &= ~UART_STOP_MASK; control_word |= stopbit; control_word &= ~UART_PARITY_MASK; control_word |= parity; WriteReg32(BASE, UART_LCR, control_word); /* DLAB End */ return 0 ; }

kevinkeryk · Answer

Hi David, MediaTek has listened to your requests and has released some limited information that is not under NDA to help designers better adopt the M4 into their overall solution: https://support.mediatek.com/AzureSphere/mt3620/M4_API_Reference_Manual/ Also, some Beta versions of the M4 Driver and Sample code is published here as well: https://github.com/MediaTek-Labs/mt3620_m4_software If anyone finds this information helpful or useful, please upvote this response so that it is more visible to the rest of the community. Best Regards, -Kevin

Fred27 · Answer

I got a reply to my email. It seems that the datasheet for the M4F cores on the MT3620 is available only under NDA. I assume it must be the same for the rest of the MT3620 as I haven't seen a datasheet anywhere. (There is a Product Brief, but that's all I've found and it's not very detailed.)

I use Azure professionally, but as my interest in Azure Sphere is from a hobbyist perspective (and it'd be good to blog about the device) it doesn't seem appropriate to go down the NDA route.

peterfenn · Answer

This is detailed in the (NDA) M4 Programmers Guide document (which refers to a spreadsheet for calculating the baud rate setting) Reviewing the UART initialization (for 115200 baud) code in one of the M4 samples which you have access to: void Uart_Init(void) { // Configure UART to use 115200-8-N-1. WriteReg32(UART_BASE, 0x0C, 0x80); // LCR (enable DLL, DLM) WriteReg32(UART_BASE, 0x24, 0x3); // HIGHSPEED WriteReg32(UART_BASE, 0x04, 0); // Divisor Latch (MS) WriteReg32(UART_BASE, 0x00, 1); // Divisor Latch (LS) WriteReg32(UART_BASE, 0x28, 224); // SAMPLE_COUNT WriteReg32(UART_BASE, 0x2C, 110); // SAMPLE_POINT WriteReg32(UART_BASE, 0x58, 0); // FRACDIV_M WriteReg32(UART_BASE, 0x54, 223); // FRACDIV_L WriteReg32(UART_BASE, 0x0C, 0x03); // LCR (8-bit word length) } The calculation is then as follows: XTAL clock frequency = 26 MHz When HIGHSPEED = 3: baud_rate = XTAL clock frequency/(SAMPLE_COUNT+1)/{DLH, DLL} i e. For that 115200 baud rate setting: baud rate = 26000000/(224+1)/1 = 115555.6 Hz // ie. 115200 + 0.3% -Peter

wizio · Answer

Thanks Peter, Can you share UART base oscilator value, baudrate formula, divider, fractional values. ... uart is partial shared via examples approximately looks like this (bits info) https://usermanual.wiki/Document/MT76x7ReferenceManual.1463370314.pdf

peterfenn · Answer

Note ! For the level of detail you are looking for, on programming the M4 cores on the MT3620, you should request the NDA MT3620 M4 Datasheet by emailing Azure.Sphere@AVNET.COM

Jan Cumps · Answer

Fred27 wrote:

... as my interest in Azure Sphere is from a hobbyist perspective (and it'd be good to blog about the device) it doesn't seem appropriate to go down the NDA route.

I also don't sign NDAs for non-professional things. Because I don't want to deal with legal, and it hinders the ability to blog.

If a supplier asks to wait for a while until a product is released, I do that. But I don't sign.

wizio · Answer

Nice Thank you Peter This need only 26Mhz and frac values https://github.com/robbie-cao/mt7687/blob/5a5f8440a5cb37d6a143ff10774e431463dd0c7c/driver/chip/mt7687/src/common/uart.c#…

akosl · Answer

Got a reply from Avnet yesterday: The full MT3620 datasheet and HW design guide as well as the M4 core datasheet and M4 core programming guide from MediaTek are still under NDA. :/

clem57 · Answer

UART rates are 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 500000, 576000, 921600, 1000000, 1152000, 1500000, and 20000000. from the MT3630 design SPI is up to 40 MHz. ADC is in preview support and not production ready. Hope this helps wizio Clem

Where do I find details on using the M4F cores on the Azure Sphere?

Top Replies