From 0b71654c22a3da3747e2306961f05d5367c2de30 Mon Sep 17 00:00:00 2001 From: Michael Buesch Date: Sat, 8 Jan 2011 23:21:55 +0100 Subject: Unify the FPGA read API Signed-off-by: Michael Buesch --- README-DEVELOPERS.lyx | 34 +++++++++++++--------------------- 1 file changed, 13 insertions(+), 21 deletions(-) (limited to 'README-DEVELOPERS.lyx') diff --git a/README-DEVELOPERS.lyx b/README-DEVELOPERS.lyx index 525117d..2f138a3 100644 --- a/README-DEVELOPERS.lyx +++ b/README-DEVELOPERS.lyx @@ -257,14 +257,17 @@ byte \end_inset as payload data. + Note that address 0x10 is fast-tracked and uses one byte less on the USB + bus. + So it is potentially faster. \end_layout \begin_layout Subsection -cmdFPGAReadRaw(address) +cmdFPGARead(address) \end_layout \begin_layout Standard -Reads a byte from the FPGA and puts it into the microcontroller's status +Reads a byte from the FPGA and puts it into the microcontroller's buffer register. \begin_inset Quotes eld @@ -275,27 +278,16 @@ address \end_inset is used for address latching on the FPGA. - The microcontroller's status register has an automagically incrementing + The microcontroller's buffer 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 (cmdReadBufferReg()) will reset the automagic + So issueing several cmdFPGARead() in a row will result in all the bytes + being put one after each other into the buffer register. + The buffer register can hold up to 64 bytes. + Reading the buffer register (cmdReadBufferReg()) will reset the automagic pointer to zero. -\end_layout - -\begin_layout Subsection -cmdFPGAReadByte() -\end_layout - -\begin_layout Standard -This is a shortcut to cmdFPGAReadRaw(0x10). - 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. + Note that address 0x10 is fast-tracked and uses one byte less on the USB + bus. + So it is potentially faster. \end_layout \begin_layout Subsection -- cgit v1.2.3