Bit 3—Reserved: Read-only bit, always read as 1.
Bits 2 to 0—I/O Control A2 to A0 (IOA2 to IOA0): These bits select the GRA function.
Bit 2
Bit 1
Bit 0
IOA2
IOA1
IOA0
Function
0
0
0
No output at compare match
(Initial value)
1
0 output at GRA compare match
*
1
1
0
1 output at GRA compare match
*
1
1
Output toggles at GRA compare match
(1 output in channel 2)
*
1,
*
2
1
0
0
GRA captures rising edge of input
1
GRA captures falling edge of input
1
0
GRA captures both edges of input
1
Notes: 1. After a reset, the output is 0 until the first compare match.
2. Channel 2 output cannot be toggled by compare match. This setting selects 1 output
instead.
10.2.12 Timer Status Register (TSR)
TSR is an 8-bit register. The ITU has five TSRs, one in each channel.
Channel
Abbreviation
Function
0
TSR0
Indicates input capture, compare match, and overflow status
1
TSR1
2
TSR2
3
TSR3
4
TSR4
GRA is an output
compare register
GRA is an input
capture register
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