From 09bf3788373c753d3eb4fb9b99af19ded1d9771d Mon Sep 17 00:00:00 2001 From: Michael Buesch Date: Fri, 2 Apr 2010 16:46:35 +0200 Subject: cmdFPGAReadRaw() does not inc the status reg pointer Document that. Signed-off-by: Michael Buesch --- README-DEVELOPERS.lyx | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'README-DEVELOPERS.lyx') diff --git a/README-DEVELOPERS.lyx b/README-DEVELOPERS.lyx index a2c62c3..8922808 100644 --- a/README-DEVELOPERS.lyx +++ b/README-DEVELOPERS.lyx @@ -258,13 +258,6 @@ address \end_inset is used for address latching on the FPGA. - The microcontroller's status register has an automagically incrementing - pointer. - So issueing several cmdFPGAReadRaw() in a row will result in all the bytes - being put one after each other into the status register. - The status register can hold up to 64 bytes. - Reading the status register (cmdReadStatusReg()) will reset the automagic - pointer to zero. \end_layout \begin_layout Subsection @@ -272,13 +265,18 @@ cmdFPGAReadByte() \end_layout \begin_layout Standard -This is a shortcut to cmdFPGAReadRaw(0x10). +This is cmdFPGAReadRaw(0x10) with auto-increment. In general it is used for payload data reading. Using cmdFPGAReadByte() instead of cmdFPGAReadRaw(0x10) is more efficient for payload reading, because on the USB bus the command is only one byte wide instead of two. So it uses up less space in the transmission queue and can thus speed up operation. + It also automagically increments the status register pointer. + So several cmdFPGAReadByte() calls in a row will result in the data put + next to each other into the status register. + This way up to 64bytes can be queued up and be read by one single status + register read. \end_layout \begin_layout Subsection -- cgit v1.2.3