Rainbow Electronics ATtiny43U - Manual (Page 136)

136
8048B–AVR–03/09
ATtiny43U
To read the Fuse High Byte (FHB), simply replace the address in the Z-pointer with 0x0003 and
repeat the procedure above. If successful, the contents of the destination register are as follows.
Refer to Table 19-4 on page 140 for detailed description and mapping of the Fuse High Byte.
To read the Fuse Extended Byte (FEB), replace the address in the Z-pointer with 0x0002 and
repeat the previous procedure. If successful, the contents of the destination register are as
follows.
Refer to Table 19-3 on page 140 for detailed description and mapping of the Fuse Extended
Byte.
18.6.3 Reading Device Signature Imprint Table from Firmware
To read the contents of the device signature imprint table, follow the below procedure:
1. Load the Z-pointer with the table index.
2. Set RSIG and SPMEN bits in SPMCSR.
3. Issue an LPM instruction within three clock cycles.
4. Read table data from the LPM destination register.
See program example below.
Note: See “Code Examples” on page 6 .
If successful, the contents of the destination register are as described in section “Device Signa-
ture Imprint Table” on page 141 .
Bit 7 6 5 4 3 2 1 0
Rd FHB7 FHB6 FHB5 FHB4 FHB3 FHB2 FHB1 FHB0
Bit 7 6 5 4 3 2 1 0
Rd FEB7 FEB6 FEB5 FEB4 FEB3 FEB2 FEB1 FEB0
Assembly Code Example
DSIT_read:
; Uses Z-pointer as table index
ldi ZH, 0
ldi ZL, 1
; Preload SPMCSR bits into R16, then write to SPMCSR
ldi r16, (1<<RSIG)|(1<<SPMEN)
out SPMCSR, r16
; Issue LPM. Table data will be returned into r17
lpm r17, Z
ret