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authorMichael Buesch <mb@bu3sch.de>2010-04-02 17:11:52 +0200
committerMichael Buesch <mb@bu3sch.de>2010-04-02 17:11:52 +0200
commit545d80cf8d13fd84cdca9f14cd69139349b9c066 (patch)
treecad538ee3357fbf53e430a22ff3c60cd5ea0f6ed /README-DEVELOPERS.lyx
parentc11884e7ff8f049e88da7a1669879a18d1ec7913 (diff)
downloadtoprammer-545d80cf8d13fd84cdca9f14cd69139349b9c066.tar.xz
toprammer-545d80cf8d13fd84cdca9f14cd69139349b9c066.zip
Revert "cmdFPGAReadRaw() does not inc the status reg pointer"
This reverts commit 09bf3788373c753d3eb4fb9b99af19ded1d9771d.
Diffstat (limited to 'README-DEVELOPERS.lyx')
-rw-r--r--README-DEVELOPERS.lyx14
1 files changed, 8 insertions, 6 deletions
diff --git a/README-DEVELOPERS.lyx b/README-DEVELOPERS.lyx
index 8922808..a2c62c3 100644
--- a/README-DEVELOPERS.lyx
+++ b/README-DEVELOPERS.lyx
@@ -258,6 +258,13 @@ 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
@@ -265,18 +272,13 @@ cmdFPGAReadByte()
\end_layout
\begin_layout Standard
-This is cmdFPGAReadRaw(0x10) with auto-increment.
+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.
- 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
bues.ch cgit interface