spi speed, which spi and does remap change anything

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zmemw16
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spi speed, which spi and does remap change anything

Post by zmemw16 » Mon Jan 01, 2018 12:27 am

background was some discussion on use of pb pins for debug and cancelling that and another blue pill and sd post with spi speed mentioned.

the 'latest' cz_ministm32 boards have both esp8266 and nrf24 connectors.

bare with me, that nrf24 connection uses pb3, pb4, pb5.
from playing with cubemx on a Black F407VET and with another f103 both with nrf24 awhile back, each of those maybe configured as either spi1 or the spi3 interface

got there - if i use 'debug_sw' those pins are now free and if i set the pins as spi1 remapped,
what clock would i get ? 36 or 18 MHz ?

stephen

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RogerClark
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Re: spi speed, which spi and does remap change anything

Post by RogerClark » Mon Jan 01, 2018 3:08 am

Core has been updated to fix that bug (a few days ago, via PR from Steve)

zmemw16
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Re: spi speed, which spi and does remap change anything

Post by zmemw16 » Mon Jan 01, 2018 11:59 am

@roger
i read the pr and checked the cores i'm using.
rest was background to spi1/spi3,
so the question i'm asking is really,
if i set the pins as spi1 remapped, what clock would i get ? 36 or 18 MHz ?
also if i setup them as spi3, it would be 18MHz ?
srp

stevestrong
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Re: spi speed, which spi and does remap change anything

Post by stevestrong » Tue Jan 02, 2018 3:39 pm

F103 does not have SPI3.
The F4 boards are working with 168MHz, so you can get up to 84MHz with SPI1 and 42MHz with SPI2/3.
The pins to which you (re)map the SPI port do no influence the frequency.

zmemw16
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Re: spi speed, which spi and does remap change anything

Post by zmemw16 » Tue Jan 02, 2018 3:58 pm

uh, cubemx and stm32f103ve say otherwise or else i wouldn't have asked the question.
also had the same from 407ve and discussion about how the interfaces are named,by mcu or as the pcb schematic names them. spi1remapped on spi3, schematic said spi1 - without realising about the remap you tend to ask why's spi3 being called spi1, well i did :D
i'd not realised about the higher spi speeds being available, i need to remember to look more closely at the cubemx clock configure tab in the future.
stephen
Configuration vet
STM32CubeMX 4.23.0
Date 01/02/2018
MCU STM32F103VETx



PERIPHERALS MODES FUNCTIONS PINS
SPI1 Full-Duplex Master SPI1_MISO PA6
SPI1 Full-Duplex Master SPI1_MOSI PA7
SPI1 Full-Duplex Master SPI1_SCK PA5
SPI2 Full-Duplex Master SPI2_MISO PB14
SPI2 Full-Duplex Master SPI2_MOSI PB15
SPI2 Full-Duplex Master SPI2_SCK PB13
SPI3 Full-Duplex Master SPI3_MISO PB4
SPI3 Full-Duplex Master SPI3_MOSI PB5
SPI3 Full-Duplex Master SPI3_SCK PB3
SYS No Debug SYS_VS_ND VP_SYS_VS_ND
SYS SysTick SYS_VS_Systick VP_SYS_VS_Systick



Pin Nb PINs FUNCTIONs LABELs
30 PA5 SPI1_SCK
31 PA6 SPI1_MISO
32 PA7 SPI1_MOSI
52 PB13 SPI2_SCK
53 PB14 SPI2_MISO
54 PB15 SPI2_MOSI
89 PB3 SPI3_SCK
90 PB4 SPI3_MISO
91 PB5 SPI3_MOSI

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