Tandy 1000 SL Technical Reference Manual page 258

EICHO
-
F E
Hex
This camnand is provided f o r diagnostic purposes.
The
keyboard
s h a l l respond with E X
Hex,
instead of Z!cknowledge, and continue
scanning t h e matrix.
SE2/RESGT STATUS INDICATORS
-
ED
H e x
This ccnrmand c o n s i s t s of one camand byte and one paramter
byte.
The
keyboard Acknowledges t h e
CarpMnd
byte, stops scanning
t h e matrix, and waits for t h e p a r a m t e r byte. Upon receiving
t h e
paramter byte, the keyboard sends an Acknowledge, sets
t h e
s t a t u s indicators, and starts scanning t h e matrix.
If
another camand is received instead of t h e parameter byte,
t h e keyboard disregards t h e
Set/Reset
S t a t u s Indicators ccnnmnd
without changing t h e present s t a t u s of t h e i n d i c a t o r s , processes
t h e new comnand, and starts scanning t h e matrix.
The
parameter
byte
is an e i g h t - b i t word
w i t h b i t s
3-7 always set
t o low.
B i t
0
is the Scroll Lock Indicator,
b i t 1
is t h e
Num
Lock Indicator, and b i t
2
is t h e
Caps
Lock Indicator.
A
high i n
each individual
b i t
i n d i c a t e s t h a t Indicator is a c t i v e and t h e
i n d i c a t o r l a q should
be
on.
0 0 0 0 0 0 1 0
PARAMETERBYTE
7
6 5 4 3 2 1 0
BITNUMBER
The above exanple shows t h e power-on d e f a u l t of t h e Tan* 3000
M;.
B i t
1 is high indicating
Num
Lock is a c t i v e and t h e Num
Lock
indicator lanp is on.
This
ccpnmand
causes t h e keyboard t o r e t u r n two i d e n t i f i c a t i o n
bytes AB83 Hex. The keyboard responds with an Acknowledge t o t h e
c d and stops scanning t h e matrix.
The
keyboard then
t r a n s n i t s t h e keyboard
ID
AB83 H e x and r e s u m s scanning t h e
matrix.
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