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-rw-r--r--src/devices/bus/mackbd/mackbd.cpp9
1 files changed, 9 insertions, 0 deletions
diff --git a/src/devices/bus/mackbd/mackbd.cpp b/src/devices/bus/mackbd/mackbd.cpp
index 76f1cebb99c..aa3713e5fd4 100644
--- a/src/devices/bus/mackbd/mackbd.cpp
+++ b/src/devices/bus/mackbd/mackbd.cpp
@@ -65,6 +65,15 @@
* 0x36: Perform self test
Peripheral responds with 0x7d (pass) or 0x77 (failure).
+ Responses to polling commands 0x10 and 0x14 have the first bit clear
+ for key down events or set for key up events.
+
+ The keypad passes polling commands 0x10 and 0x14 on to the keyboard
+ if it has no response to send. If the keypad has a key transition
+ to report, it responds with the octet 0x79. After receiving this
+ response, the host should send command 0x10 to receive the key
+ transition event from the keypad.
+
Additionally, if bit 5 of the octet sent to the peripheral is set
(0x40), the octet is passed on to a daisy-chained peripheral with
this bit cleared. The response from the daisy-chained peripheral is