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authorMichael Buesch <mb@bu3sch.de>2011-01-08 23:21:55 +0100
committerMichael Buesch <mb@bu3sch.de>2011-01-08 23:21:55 +0100
commit0b71654c22a3da3747e2306961f05d5367c2de30 (patch)
tree6b36de27a4d05655974ed72ff146c82f64c4a24f /README-DEVELOPERS.lyx
parenteb9de8d8a075211638d5a4b1c433855bb41be610 (diff)
downloadtoprammer-0b71654c22a3da3747e2306961f05d5367c2de30.tar.xz
toprammer-0b71654c22a3da3747e2306961f05d5367c2de30.zip
Unify the FPGA read API
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Diffstat (limited to 'README-DEVELOPERS.lyx')
-rw-r--r--README-DEVELOPERS.lyx34
1 files changed, 13 insertions, 21 deletions
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
bues.ch cgit interface