Serial programmer for Ti TMS320f28xx mcus.

[justjason]

Does anyone have any info on the connections for required on the programmer side for flashing the Ti TMS320f280021 MCU over serial. ?
I am not sfinding anything about what is required on the programmer side with regards to where the pins for controlling the boot selection mode are connected. eg
Where would I be connecting these pins on the programmer side - CTR RTS ... ??

[darkspr1te]

you should check this pdf out
https://www.ti.com/lit/an/spraca2a/spraca2a.pdf?ts=1694550221445&ref_url=https%253A%252F%252Fwww.google.com%252F

[justjason]

Thanks for the reply. It looks like it may be a simple case of manually setting the boot pins to the desired mode and the then I can send the data over to the MCU. Somewhere in a different  data sheet I found reference of first sending an "A" in the beginning to trigger the auto baud rate negotiation. I will give that a try tomorrow.

[darkspr1te]

Yes, you just follow that supplied truth table and set your desired boot mode, most mcu use this trick as do SOC's like rockchip/qualcomm etc.


darkspr1te

[mtwieg]

The first thing the MCU does upon exiting reset is read the two bootmode pins to determine which boot mode it will use. As the table implies, to enter the SCI boot ROM, hold GPIO37 low and GPIO34 high, initiate a reset with XRSn, then once the MCU is in the SCI bootloader you can release those two GPIO.

The ROM bootloader uses specific pins for TX and RX, this should be explained in the datasheet.

Importantly, to use the SCI boot ROM you do not need to touch any of the OTP memory inside the MCU.