MMWCAS-RF-EVM: Can I set the anyone of the 4 XWR2243 chip as the Master or single chip for testing?

Hi Daning, 

Only UI_1 has its FMCW_CLKOUT and FMCW_SYNCOUT 20 GHz LO source routed to the other three devices. So this is the only VCO enabled master

Only U1_1 (AWR #1) and U1_3 (AWR #3) can be configured in master mode as they are the only two devices with their own dedicated 40 MHz crystal clock source (Y1 and Y2). This was done to add additional flexibility since can be used to separate out the 40 MHz source device (U1_3) from the LO generating device (U1_1). 

In the example Cascade MIMO configuration script (C:\ti\mmwave_studio_02_01_00_00\mmWaveStudio\Scripts\Cascade\Cascade_Configuration_MIMO.lua) near the top of the file are a few lists used to select the master vs. slave mode. 

----------------------------------------User Constants----------------------------------------------------
       
dev_list					=	{1, 2, 4, 8}                    -- Device map
RadarDevice					=	{1, 1, 1, 1}			-- {dev1, dev2, dev3, dev4}, 1: Enable, 0: Disable
	
cascade_mode_list				=	{1, 2, 2, 2}			-- 0: Single chip, 1: Master, 2: Slave

The cascade_mode_list list allows the user to select which mode they want each device to be programmed in. 

Please let me know if that answers your questions. 

Thank you,

-Randy

Hi Daning, 

Yes, you can configure any device into any mode (single-device, cascade master or cascade slave) as long as the device is booted properly first. 

In the case of our Cascade EVM, we typically bring-up the AWR #1 first and configure it to cascade master mode. This will setup AWR #1 to enable the OSC_CLKOUT output and fan this out to the other three devices as their 40 MHz source. Then we boot the other three devices and configure them in cascade slave mode. 

On our EVM, only devices #1 and #3 have their own 40 MHz crystal source. Those devices can boot on their own, with respect to clocking. But the other slave devices must receive their 40 MHz source from the device #1 in master mode, or from an external source over the host board connectors.  

Once a device is booted, there is nothing that prevents a user from configuring those devices as single-device, master or slave devices, even if they are not routed on the PCB to function in those modes. 

Please let me know if that helps. 

Thank you,

-Randy

Hi Daning, 

In the case of our MMWCAS-RF-EVM the answer is no. AWR #2 and AWR #4 cannot be booted or configured without first supplying a 40 MHz source from AWR #1. 

The AWR devices do not have their own internal crystal source. Each AWR device needs to be provided a 40 MHz source for basic functionality. It does not matter where that source comes from, but it must be provided. For example, on the MMWCAS-RF-EVM design, each AWR device either has a connected 40MHz crystal and/or the device receives a 40 MHz from the LMK00804B clock distribution generated by the master AWR U1_1.  

If you have not done so already, I would suggest reading through the AWR2243 Cascade architecture application note (http://www.ti.com/lit/an/swra574b/swra574b.pdf) and the AWR2243 data. I think that will help you understand the necessary system-level considerations in the cascaded AWR systems. 

Thank you,

-Randy