AM3356: UART configuration

g.f.

Part Number: AM3356

Hi,

My customer want to test the UART transmit operation without using FIFO and DMA.
They are following the step of UART Programming Model written in TRM page.4367
"19.4.1.1.3 Protocol, Baud Rate, and Interrupt Settings" as follow:

1.UART_MDR1［2:0］set 0x7
2.UART_LCR set 0x00BF
3.UART_EFR [4] ENHANCED_EN bit set 1
4.UART_LCR set 0x0000
5.UART_IER set 0x0000
6.UART_LCR set 0x00BF
7.set 0x39 to DLL, set 0x01 to DLHに0x01 (313=0x139：9600bps)
8.UART_LCR set 0x0000
9.UART_IER set 0x0000
10.UART_LCR set 0x00BF
11.UART_EFR [4] ENHANCED_EN bit set 0
12.UART_LCR set 0x0033 (non-parity, 1 stop-bit)
13.UART_MDR1[2:0] set 0 (UARTx16 mode)

After above configuration, they wrote 1byte data to THR register to check the transmit operation.
But no signal comes out from the TXD pin.
Are above setup steps correct? Or are they missing some setups?

They are using UART3 for this test and configuring in GEL file(Non-OS used).
The pin mux and PER_UART3_CLKOUT configuration seems fine.

best regards,
g.f.

over 6 years ago

0 Biser Gatchev-XID over 6 years ago

TI__Guru**** 393215 points

Hi,

You can refer to the Starterware examples in the RTOS SDK package.

0 g.f. over 6 years ago in reply to Biser Gatchev-XID

Guru 15520 points

Hi Biser,

Thank you for the reply.
The examples in SDK are using FIFO and EDMA but my customer are not using it.
We want to know the setup steps which I mention above are correct or not.

best regards,
g.f.

0 Rahul Prabhu over 6 years ago in reply to g.f.

TI__Guru** 116770 points

If FIFO And DMA is not required then you can use the bare-metal examples in AM3356 diagnostic package here:
pdk_am335x_1_0_13\packages\ti\board\diag\uart

I can understand the customer doesn`t want to use DMA but what is the reason for not using UART FIFO ? Disabling DMA is supported in the driver but disabling FIFO is not. We use FIFO trigger of 8 for RX but users can specify size < trigger level to receive smaller data sizes.

Regards,
Rahul

0 g.f. over 6 years ago in reply to Rahul Prabhu

Guru 15520 points

Hi Rahul,

Thank you for the information about the examples.
There are no reason for not using the FIFO.
They just want to test their hardware with simple software setups.

best regards,
g.f.

Processors

Processors forum

AM3356: UART configuration