B4
LS
Writing a zero in bit 4 causes the selected counter(s) to latch the
current condition of its Control Register, Null Count, and Output
into the Status Register. The next read of the counter results in the
contents of the Status Register being read.
Writing a zero in bit 5 causes the selected counter(s) to latch to the
state of the CE in COL and COH.
Read as ones.
B5
LC
B6-B7
1
Status Byte
The format of the Status Byte command is shown in Figure 6-9.
B7
B6
B5
B4
B3
B2
B1
B0
________ ________
_________________
___________________________
________
BCD
Binary Coded Decimal
M<2:0> Mode Counter
F<0:1> Flag Command
NC
Null Count Flag
OUT
Out Signal
bits:
B0
BCD
Bit 0 indicates the CE is in operation in BCD format.
B2-B3
M<0:2>
These three bits reflect the mode of the counter and are interpreted in
the same manner as in Write command operations.
Bits 4-5 contain the F0 and F1 command bits, which were written
to the Command Register of the counter during initialization. This
information is useful when determining whether the high byte, low
byte, or both must be transferred during counter read/write
operations.
Bit 6 contains the condition of the Null Count flag. This flag is used
to indicate the contents of the CE are valid. NC is set to a one during
a write to the Control Register or the counter. NC is cleared to a
zero whevever the counter is loaded from the counter input registers.
Bit 7 contains the state of the OUT signal of the counter.
B4-B5
F<0:1>
B6
NC
B7
OUT
Figure 6-9.
Status Byte Command
I
Programming the Counter Timer Controller
Real Time Clock and Internal Timer Registers
6-14
Revision 3.0
P R E L I M I N A R Y
Chips and Technologies, Inc.