GLK: Default Flow Control Values
Posted: Thu Sep 17, 2009 5:56 am
I am trying to re-create an off-the-shelf condition for the GLK24064. The command 'Turn Flow Control On' (0xFE 0x3A) has two parameters: almost full and almost empty. Can you tell me what are the default values for these two bytes?
EDIT: Ignore the above question...I see that Flow Control is default off. The paragraph below is still valid.
I am also noticing an anomaly that may or may not have been seen before because I may communicating to the display in an obscure manner. I am using the command 'Drawing a Bitmap Directly' (0xFE 0x64) to draw an entire screen-filling bitmap (240 x 64, 1920 bytes) at 115,200. I would expect that with flow control on that the XOFF/XON (0xFE/0xFF) would regulate the data flow to prevent buffer overflow. What I am noticing is that XOFF/XON characters appear AFTER the transmission completes, as though the on-board processor wants to send XOFF to the host, but can't because another input character has been detected. (BTW, I'm glad this is the way it works.) I was able to create a workaround by delaying every 512 bytes, in which I never see the XOFF's. I just wanted to point this out; it's not a problem to me because the workaround works.
Thanks, Vernon.
EDIT: Ignore the above question...I see that Flow Control is default off. The paragraph below is still valid.
I am also noticing an anomaly that may or may not have been seen before because I may communicating to the display in an obscure manner. I am using the command 'Drawing a Bitmap Directly' (0xFE 0x64) to draw an entire screen-filling bitmap (240 x 64, 1920 bytes) at 115,200. I would expect that with flow control on that the XOFF/XON (0xFE/0xFF) would regulate the data flow to prevent buffer overflow. What I am noticing is that XOFF/XON characters appear AFTER the transmission completes, as though the on-board processor wants to send XOFF to the host, but can't because another input character has been detected. (BTW, I'm glad this is the way it works.) I was able to create a workaround by delaying every 512 bytes, in which I never see the XOFF's. I just wanted to point this out; it's not a problem to me because the workaround works.
Thanks, Vernon.