ISP speed

[sirurx]

Hi,

Why is that maximum ISP serial speed for LPC11E68 (using boot ROM) is 115200 while USART0 can support speeds at least 3Mbit?

BR,

Ergo

[ckphua]

The main reason is the legacy of PC baud rate in the early 2000, when LPC family with UART Bootloader was started. Of course the cable length plays a role (and you will need the transceiver when using the old RS232 port). Therefore if you want to get a higher baud rate for your In Application update, you can do it using your own UART routines.

[sirurx · Accepted solution]

Therefore to have reasonable speed for production programming:

1. Program own bootloader @ 115kbaud.

2. Reboot to new bootloader and program main image using that.

This can actually work, just extra cost for developing own bootloader.

Also loss of some space in chip for bootloader.

[jeremyzhou]

Hi Ergo Pehtla ,

The parameter value of the UART baud rate shouldn't be others except for 9600, 19200, 38400, 57600, 115200.

Hope it helps.
Have a great day,
Ping

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[sirurx]

Hi Ping,

This did not answer my question: why it's limited as hardware supports higher speeds?

BR,

Ergo

[jeremyzhou]

Hi Ergo,

Thanks for your reply.

The 115200 is the maximum baud rate for ISP mode by considering the balance the transmission distance and error ratio.

Hope it helps.
Have a great day,
Ping