DS785UM1
26-7
Copyright 2007 Cirrus Logic
Keypad Interface
EP93xx User’s Guide
2
6
2
6
26
Address:
0x808F_0000
Default:
0x0000_0000
Definition:
Key scan initialization register.
Bit Descriptions:
RSVD:
Reserved. Unknown during read.
DBNC:
De-bounce start count. This value is used to pre-load the
de-bounce counter. The de-bounce counter counts the
number of consecutive scans that decoded the same
keys. Terminal count for the de-bounce counter is 0xFF.
Terminal count indirectly generates a key scan interrupt. A
pre-load value of 0xFC will cause the key scan circuitry to
count 3 identical consecutive keypad scans.
DIS3KY:
Disable 3 Key reset. Setting this bit high disables the three
key reset output to the watchdog reset block. Setting it
back low re-enables it.
DIAG:
Key scan diagnostic mode. Setting this bit high allows key
scanning to be directly controlled through the key register
by writes from the ARM Core. The DIAG.KEY[5:0] value is
written by the ARM Core. Then the KeyRegister.K bit is
read to determine if there is a key press. The result from
reading the KeyRegister.K bit is not hardware de-bounced.
BACK:
Key scan back driving enable. Setting this bit high enables
the key scanning logic to back drive the row and column
pins of the chip high during the first two column counts in
the row/column counter.
T2:
Test mode bit. When this bit is set to “1”, the counter
RC_COUNT is advanced by 8 counts when EN is active.
The effect is that only column 0 is checked in each row.
This test mode allows a faster test of the ROW pins.
NA:
Not Assigned. These bits will read back the value written.
Summary of Contents for EP93 Series
Page 28: ...P 6 DS785UM1 Copyright 2007 Cirrus Logic Preface EP93xx User s Guide PP P ...
Page 162: ...5 36 DS785UM1 Copyright 2007 Cirrus Logic System Controller EP93xx User s Guide 55 5 ...
Page 576: ...15 18 DS785UM1 Copyright 2007 Cirrus Logic UART2 EP93xx User s Guide 1515 15 ...
Page 634: ...17 38 DS785UM1 Copyright 2007 Cirrus Logic IrDA EP93xx User s Guide 1717 17 ...
Page 648: ...19 6 DS785UM1 Copyright 2007 Cirrus Logic Watchdog Timer EP93xx User s Guide 1919 19 ...
Page 688: ...21 32 DS785UM1 Copyright 2007 Cirrus Logic I2S Controller EP93xx User s Guide 2121 21 ...
Page 790: ...27 20 DS785UM1 Copyright 2007 Cirrus Logic IDE Interface EP93xx User s Guide 2727 27 ...
Page 808: ...28 18 DS785UM1 Copyright 2007 Cirrus Logic GPIO Interface EP93xx User s Guide 2828 28 ...