LPC2388 UART2 Issue

danzarate — Mon, 10 Aug 2020 22:19:26 GMT

Hi all,

I am looking to get UART2 working on the LPC2388 microcontroller.

Currently, UART0 and UART1 works on it as they are provided in the sample code bundle (using uVision -- the first link under Embedded Software):

Arm7™ with 512 kB flash, 98 kB SRAM, Ethernet, USB 2.0 Device/Host/OTG, CAN, and 10-bit ADC | NXP

After going through the datasheet and user's manual (also given by the link above under the Documentation tab), I made some additions to include UART2 functionality. I can provide snippets of code upon request, but in short, here are the additions I made to start:

I am enabling UART2 within the PCONP register (PCONP |= 0x01000000)
I am enabling TXD2 and RXD2 within the PINSEL0 register (PINSEL0 |= 0x00500000)
I am installing the interrupt handler using UART2's number (it's #defined as 28 in the header file given by NXP)
The way I am initializing UART2 is the same way the sample code is initializing UART0 and UART1, with the exception of the registers (it's U2***, instead of U1*** and U0***).
The way I am creating UART2's handler is the same way the sample code is creating the handlers for UART0 and UART1 (once again, with the exception of the registers)
The way I am sending out UART2's data is the same way the sample code is sending out the data for UART0 and UART1 ("")

Here some other notes that may/may not help:

Same baud rates and frequencies are being used
I have confirmed that data is going into U2THR register (well, sort of.)
The code seems like it is sending out the data, but I am not receiving it on the other side (RealTerm)
- I see data coming out for UART0 and UART1, but nothing for UART2
Code is not being blocked anywhere

I did not see anything unique to UART2 in the user's manual that was not apparent in UART0 and UART1 other than the fact that it is off by default. I know that using an oscilloscope is one of the next options, but I want to rule out everything software related before it comes to that point.

Any insight on this is greatly appreciated.

Thank you,

Dan

Re: LPC2388 UART2 Issue

xiangjun_rong — Wed, 12 Aug 2020 04:12:02 GMT

Hi, Dan,

If you route the uart2 pins to P2.8/P2.9, what is the result?

BTW, can you enter uart2 transmitter ISR? can you see the signal of uart2 TXD via scope?

Hope it can help you

XiangJun Rong

Re: LPC2388 UART2 Issue

danzarate — Wed, 12 Aug 2020 18:24:57 GMT

XiangJun,

Switching to P2.8 and P2.9 for the pins worked! The issue was actually on my side as I just misread a schematic. I did not notice the 2nd pair of TXD2/RXD2. I can also see that the code is going into the transmitter ISR. All verified with a scope. Thank you!

Dan

NXP DesignsのトピックLPC2388 UART2 Issue

LPC2388 UART2 Issue

Re: LPC2388 UART2 Issue

Re: LPC2388 UART2 Issue