LPC MicrocontrollersのトピックRe: ISP speed

ISP speed

sirurx — Tue, 20 Sep 2016 13:38:35 GMT

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

Re: ISP speed

jeremyzhou — Mon, 26 Sep 2016 06:14:58 GMT

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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Re: ISP speed

sirurx — Fri, 30 Sep 2016 13:23:34 GMT

Hi Ping,

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

BR,

Ergo

Re: ISP speed

jeremyzhou — Sat, 01 Oct 2016 03:43:37 GMT

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

Re: ISP speed

ckphua — Mon, 03 Oct 2016 16:56:36 GMT

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.

Re: ISP speed

sirurx — Tue, 04 Oct 2016 09:28:58 GMT

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.