MC33780 Datasheet, PDF (27/37 Pages) Freescale Semiconductor, Inc – Dual DBUS Master with Differential Drive and Frequency Spreading

FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
~EN or ABORT or RSTB ACTIVE/
R_PUSH_PTR = 0;
R_POP_PTR = 0;
R_FIFO_EMPTY = TRUE;
R_FIFO_POP & R_POP_PTR = R_PUSH_PTR-1/
R_POP_PTR = R_POP_PTR+1;
R_FIFO_EMPTY = TRUE;
RX_IDLE
STATE TRANSISTIONS OCCUR
ON NEGATIVE EDGES OF R_FIFO_PUSH
AND R_FIFO_POP
R_FIFO_PUSH/
R_PUSH_PTR = R_PUSH_PTR+1;
R_FIFO_EMPTY = FALSE;
R_FIFO_POP & R_POP_PTR != R_PUSH_PTR-1/
R_POP_PTR = R_POP_PTR+1;
RX_NOT_EMPTY
R_FIFO_PUSH & R_PUSHPTR != R_POP_PTR-1/
R_PUSH_PTR = R_PUSH_PTR+1;
R_FIFO_POP/
R_FIFO_POP = R_FIFO_POP+1;
OVERFLOW = FALSE;
R_FIFO_PUSH & R_PUSH_PTR = R_POP_PTR-1/
R_PUSH_PTR = R_PUSH_PTR+1;
RX_FULL
Figure 23. State Diagram of Receive FIFO
REGISTER AND BIT DESCRIPTIONS
The 33780 has 22 registers, shown in Table 8. The lower
8 (00000 through 00111) are compatible with the 8 registers
in the 68HC55. The remaining registers (01000 through
10101) are needed for the additional modes of operation.
Table 8. Register List
Register
Address
Register Name
Register Definition
00000
D0H
DBUS 0 upper byte
00001
00010
D0L
D1H
DBUS 0 lower byte
DBUS 1 upper byte
00011
00100
D1L
D01STAT
DBUS 1 lower byte
DBUS 0 and 1 status
00101
D0CTRL
DBUS 0 control
00110
00111
D1CTRL
DEN
DBUS 1 control
DBUS enable bits
01000
01001
D0POLY
D1POLY
DBUS 0 CRC polynomial
DBUS 1CRC polynomial
01010
D0SEED DBUS 0 CRC seed
01011
01100
D1SEED
D0LENGTH
DBUS 1 CRC seed
DBUS 0 short word and CRC lengths
01101
01110
D1LENGTH
D0SSCTRL
DBUS 1 short word and CRC lengths
DBUS 0 spread spectrum control
01111
D1SSCTRL DBUS 1spread spectrum control
10000
10001
D0OFFSETH DBUS 0 spread spectrum offset high
D0OFFSETL DBUS 0 spread spectrum offset low
10010
10011
D1OFFSETH DBUS 1 spread spectrum offset high
D1OFFSETL DBUS 1 spread spectrum offset low
10100
10101
D0SSUD
D1SSUD
DBUS 0 spread spectrum up/down counter
DBUS 1 spread spectrum up/down counter
Analog Integrated Circuit Device Data
Freescale Semiconductor
33780
27