
171
XMEGA A [MANUAL]
8077I–AVR–11/2012
14.12.15 PERH – Period register High
Bit 7:0 – PER[15:8]: Period high byte
These bits hold the MSB of the 16-bit period register.
14.12.16 CCxL – Compare or Capture x register Low
The CCxH and CCxL register pair represents the 16-bit value, CCx. These 16-bit register pairs have two functions,
depending of the mode of operation.
For capture operation, these registers constitute the second buffer level and access point for the CPU and DMA.
For compare operation, these registers are continuously compared to the counter value. Normally, the outputs form the
comparators are then used for generating waveforms.
CCx registers are updated with the buffer value from their corresponding CCxBUF register when an UPDATE condition
occurs.
Bit 7:0 – CCx[7:0]: Compare or Capture x low byte
These bits hold the LSB of the 16-bit compare or capture register.
14.12.17 CCxH – Compare or Capture x register High
Bit 7:0 – CCx[15:8]: Compare or Capture x high byte
These bits hold the MSB of the 16-bit compare or capture register.
14.12.18 PERBUFL – Timer/Counter Period Buffer register Low
The PERBUFH and PERBUFL register pair represents the 16-bit value, PERBUF. This 16-bit register serves as the
buffer for the period register (PER). Accessing this register using the CPU or DMA will affect the PERBUFV flag.
Bit 7:0 – PERBUF[7:0]: Period Buffer low byte
These bits hold the LSB of the 16-bit period buffer register.
Bit
7
65
432
10
+0x27
PER[15:8]
Read/Write
R/W
Initial Value
1
11
111
11
Bit
76543210
CCx[7:0]
Read/Write
R/W
Initial Value
00000000
Bit
765432
1
0
CCx[15:8]
Read/Write
R/W
Initial Value
000000
0
Bit
7
6
543
21
0
+0x36
PERBUF[7:0]
Read/Write
R/W
Initial Value
1