Extended Z-Pointer Register

This register is concatenated with the Z-register for indirect addressing (LD/LDD/ST/STD) of the whole data memory space on devices with more than 64 KB of data memory. If the device supports more than 64 KB of program memory, the RAMPZ register extends the Z-pointer to address the entire program memory using the ELPM/SPM instructions. For more details regarding the ELPM/SPM instructions usage, refer to the instruction set summary.

This register is not available if the data memory and program memory in the device are less than 64 KB.

Name:
RAMPZ
Offset:
0x0B
Reset:
0x00
Access:
-
Bit76543210
RAMPZ[7:0]
AccessR/WR/WR/WR/WR/WR/WR/WR/W
Reset00000000

Bits 7:0 – RAMPZ[7:0]: Extended Z-pointer Address Bits

Extended Z-pointer Address Bits

These bits hold the MSB of the 24-bit address created by RAMPZ and the 16-bit Z-register. Only the number of bits required to address the available data and program memory is implemented for each device. Unused bits will always read ‘0’.

Note:
  1. 1.The LPM instruction is not influenced by the RAMPZ setting.