3 psc output behavior during reset – Rainbow Electronics ATmega64C1 User Manual
Page 291
291
7647A–AVR–02/08
ATmega32/64/M1/C1
Note:
1. See
for BODLEVEL Fuse decoding.
24.3
PSC Output Behavior During Reset
For external component safety reason, the state of PSC outputs during Reset can be pro-
grammed by fuses PSCRB, PSCARV & PSCBRV.
These fuses are located in the Extended Fuse Byte ( see
If PSCRB fuse equals 1 (unprogrammed), all PSC outputs keep a standard port behaviour. If
PSC0RB fuse equals 0 (programmed), all PSC outputs are forced at reset to low level or high
level according to PSCARV and PSCBRV fuse bits. In this second case, the PSC outputs keep
the forced state until POC register is written.
See “PSC Output Configuration – POC” on page
PSCARV (PSCOUTnA Reset Value) gives the state low or high which will be forced on
PSCOUT0A, PSCOUT1A and PSCOUT2A outputs when PSCRB is programmed. If PSCARV
fuse equals 0 (programmed), the PSCOUT0A, PSCOUT1A and PSCOUT2A outputs will be
forced to high state. If PSCRV fuse equals 1 (unprogrammed), the PSCOUT0A, PSCOUT1A
and PSCOUT2A outputs will be forced to low state.
PSCBRV (PSCOUTnB Reset Value) gives the state low or high which will be forced on
PSCOUT0B, PSCOUT1B and PSCOUT2B outputs when PSCRB is programmed. If PSCBRV
fuse equals 0 (programmed), the PSCOUT0B, PSCOUT1B and PSCOUT2B outputs will be
forced to high state. If PSCRV fuse equals 1 (unprogrammed), the PSCOUT0B, PSCOUT1B
and PSCOUT2B outputs will be forced to low state.
BODLEVEL2
2
Brown-out Detector trigger
level
1 (unprogrammed)
BODLEVEL1
1
Brown-out Detector trigger
level
1 (unprogrammed)
BODLEVEL0
0
Brown-out Detector trigger
level
1 (unprogrammed)
Table 24-4.
Extended Fuse Byte
Extended Fuse Byte
Bit No
Description
Default Value
Table 24-5.
PSC Output Behavior During and after Reset until POC register is written
PSCRB
PSCARV
PSCBRV
PSCOUTnA
PSCOUTnB
unprogrammed
X
X
normal port
normal port
programmed
unprogrammed
unprogrammed
forced low
forced low
programmed
unprogrammed
programmed
forced low
forced high
programmed
programmed
unprogrammed
forced high
forced low
programmed
programmed
programmed
forced high
forced high
BODLEVEL2
2
Brown-out
Detector
trigger level
1
(unprogramme
d)
BODLEVEL1
1
Brown-out
Detector
trigger level
1
(unprogramme
d)
BODLEVEL0
0
Brown-out
Detector
trigger level
1
(unprogramme
d)