CD2481
—
Programmable Four-Channel Communications Controller
6
Datasheet
9.4.2
9.4.3
9.4.4
Interrupt Registers.............................................................................................159
9.5.1
General Interrupt Registers..................................................................159
9.5.2
Receive Interrupt Registers..................................................................163
9.5.3
Transmit Interrupt Registers.................................................................175
9.5.4
Modem Interrupt Registers...................................................................179
DMA Registers..................................................................................................182
9.6.1
DMA Mode Register (DMR) .................................................................182
9.6.2
Bus Error Retry Count (BERCNT)........................................................182
9.6.3
DMA Buffer Status (DMABSTS)...........................................................183
9.6.4
DMA Receive Registers.......................................................................184
9.6.5
DMA Transmit Registers......................................................................189
Timer Registers.................................................................................................197
9.7.1
Timer Period Register (TPR)................................................................197
9.7.2
Receive Time-Out Period Register (RTPR)
–
Async Modes Only .......197
9.7.3
General Timer 1 (GT1)
–
Sync Modes Only.........................................198
9.7.4
General Timer 2 (GT2)
–
Sync Modes Only.........................................199
9.7.5
Transmit Timer Register (TTR)
–
Async Modes Only ..........................200
Electrical Specifications
......................................................................................201
10.1
Absolute lectri Maximum Ratings (
Revision B at 35 MHz
) ..............................201
10.2
DC Electrical Characteristics (
Revision B at 35 MHz
).....................................201
10.3
AC Electrical Characteristics (
Revision B at 35 MHz
) .....................................202
10.4
Absolute Maximum Ratings (
Revisions B and D at 60 MHz
)..........................203
10.5
DC Electrical Characteristics (
Revisions B and D at 60 MHz
)........................204
10.6
AC Electrical Characteristics (
Revisions B and D at 60 MHz
) ........................205
Package Specifications
.......................................................................................215
Ordering Information Example
.........................................................................216
Special Transmit Command Register (STCR) .....................................150
Channel Status Register (CSR) ...........................................................153
Modem Signal Value Registers (MSVR)..............................................158
9.5
9.6
9.7
10.0
11.0
12.0
Index
.......................................................................................................................................217
Figures
1
2
3
4
5
6
7
8
9
10
11
12
13
Functional Block Diagram ...................................................................................11
Host Read Cycle .................................................................................................38
Host Write Cycle .................................................................................................39
Interrupt Acknowledge Cycle ..............................................................................41
Bus Acquisition Cycle..........................................................................................47
Data Transfer Timing ..........................................................................................47
Transmitter A and B Buffers................................................................................50
Receiver A and B Buffers....................................................................................53
DMA Transmit Buffer Selection...........................................................................57
Bit Rate Generator/DPLL ....................................................................................62
Data Encoding.....................................................................................................66
Transmit Data With External Clock In .................................................................66
Transmit Data With External Clock Out ..............................................................66