customer said:Part of the design we’re working on is meant to support a pair of synchronous UART channels (clock received into the micro), operating at a high baud rate (1.6 MBaud). We’ve been unable to find a nice way of supporting this with the TI microcontrollers we’re considering (LM3S5632 or LM4F131E5QR), do you know if there’s a way to synchronize the UART ports on the device to an external clock? We’ve also looked at the SSI, but we are skeptical that we can make that work as the clock master is not providing a frame synching signal. The interface we’re receiving is really a synchronous UART with CLK, Rx and Tx signals only, and in order for the interface to work properly, we must clock out and receive our data with appropriate skew with regards to the CLK signal.
I would appreciate your thoughts on how either the LM3S5632 or the LM4F131E5QR may be configured to support such an interface.
The LM4F131E5QR controller includes eight Universal Asynchronous Receiver/Transmitter (UART) but no Universal Synchronous/Asynchronous Receiver/Transmitter (USART). Synchronous serial communications would typically be done with the Synchronous Serial Interface (SSI).
At first glance, I am not aware of a way to synchronize the UART ports on a device like the LM4F131E5QR to an external clock.
UARTSysClk is the system clock connected to the UART... By default, this will be the main system clock... Alternatively, the UART may be clocked from the internal precision oscillator (PIOSC), independent of the system clock selection.
Stellaris LM4F131E5QR Microcontroller Data Sheet (Rev. B)
Page 823 of 1250
The programmable baud-rate generator allows for speeds up to 10 Mbps.
Stellaris LM4F131E5QR Microcontroller Data Sheet (Rev. B)
Page 820 of 1250
Will any of the devices be half-duplex, receive only or transmit only?
I'm not sure I understand exactly you communication plan? Do you have a simple block diagram that would illustrate how you would like this to be configured?
Over what distance would each connection be?
