ISP and Boot modes

[lpcware]

Content originally posted in LPCWare by sasa.bremec on Mon Oct 28 02:26:30 MST 2013
In design process of our new product and reading LPC43xx manual I've found a notation about ISP programing mode using UART0 that it is not clear.

Table 4 (pg. 65)
If the chip is booted from the device connected to USART0 pins P2_0 (Tx) and P2_1 (Rx)

Question is P2_0 is located as T16 pin and P2_1 as N15, what happens if I connect USART0 Rx and Tx signals to the different location (A2 and A3) will the ISP boot still OK ???


Thanks, Sasa

[floydlau]

Is there a solution or work-around for this USART0 and EMC_A12/A13 pin conflict these days?  Thank you.

[lpcware]

Content originally posted in LPCWare by Hydron on Mon Nov 04 19:22:48 MST 2013
We had the same problem, and ended up using UART3 as a boot UART instead - it doesn't have the nice ISP features but you can load programs into ram to extend it's functionality. To get into this mode we had a simple circuit to change the boot source resistors from SPIFI to UART3 when a certain button was pressed at power-on. Somewhere on the LPC43xx or LPC18xx forums is a useful little bootloader a Japanese guy wrote which you can load using the UART boot method and then emulate the ISP functions, as well as program SPIFI flash.

This is quite an irritating design decision by NXP - please think about the pin conflicts for these two important functions next time!

[lpcware]

Content originally posted in LPCWare by sasa.bremec on Mon Nov 04 02:18:13 MST 2013
Tha,  thanks for the answer.

This is what I was afraid of, pins P2.0 (T16) and P2.1 (N15) are the only posibility for the EMC A12 and A13 signals. :(

Anyway I will try to solve this.

Thanks Sasa

[lpcware]

Content originally posted in LPCWare by tha on Tue Oct 29 19:11:56 MST 2013
No, that will not work.  The ISP mode will map the UART0 pins to its default pins, in this case P2.0 and P2.1