
206
Agere Systems Inc.
T8302 Internet Protocol Telephone
Advanced RISC Machine (
ARM
)
Data Sheet
July 2001
15 Synchronous Serial Interface (SSI)
(continued)
15.2.3.4 SCOD
Bit 4 of
SSI control register 2
is the
SCK
open-drain (
SCOD
) bit. This bit selects open-drain or direct-drive output
from
SCK
when in master mode. If bit 4 is 0,
SCK
is direct-drive. If bit 4 is 1,
SCK
is open-drain.
Table 185. SSI Control Register 2
Note: On all resets, bit 0 of SSI control register 2 is set to 1 all other bits are set to 0.
Table 186. SSI Interrupt Register
Address 0xE000 4008
3
MDOD
Bit #
Name
Bit #
31:5
4
31:5
RSVD
Name
RSVD
SCOD
4
2
1
0
SCOD
RSVD
Description
FASTCLEAR
SSN
Reserved.
SCOD bit.
This is the
SCK
open-drain (
SCOD
) bit. This bit selects open-drain or direct-
drive output for
SCK.
If bit 4 is 0 when in master mode,
SCK
is direct-drive.
If bit 4 is 1, SCK is open-
drain
.
When an open-drain I/O buffer is used, the
SCK
output will be open-drain, regardless of
the state of bit 4.
MDOSDI
and
MDISDO
output.
This bit selects open-drain or direct-drive output, for
MDOSDI
and
MDISDO
when they are outputs.
If bit 3 is 0,
MDOSDI
(master) or
MDISDO
(slave) is direct-drive.
If bit 3 is 1,
MDOSDI
or
MDISDO
are open-drain.
3
MDOD
When an open-drain I/O buffer is used, the
MDISDO/MDOSDI
output will be open-
drain, regardless of the state of bit 3.
Reserved.
Clear bit.
This bit clears to 0 after reset. If this bit is set to 1, it is not necessary to
write
the
MODF
and
SDONE
bits of
the interrupt register
.
This bit is set for DMA operations with the SSI.
SSN
state.
SSN
of
SSI control register 2
always reflects the state of the
SSN
chip,
regardless of whether
SSNEN
is 0 or 1.
2
1
RSVD
FASTCLEAR
0
SSN
Address 0xE000 4010
6
WCOLL
Bit #
Name
Bit #
31:8
7
31:8
RSVD
7
5
4
3:0
SDONE
MODF
RD_ORUN
RSVD
Name
RSVD
SDONE
Description
Reserved.
Serial transfer complete interrupt.
If 1, the serial transfer is completed.
If 0, no transfer pending or a transfer is in progress.
Cleared by writing a 1.
Write collision error interrupt.
If 1, a write to the
SSI data register
occurred while a serial transfer was in progress.
If 0, no error was detected.
Cleared by writing a 1.
6
WCOLL