III PERIPHERAL BLOCK: MONITORED MOBILE ACCESS INTERFACES

Data Buffers

PHS communications uses two 80-byte buffers each for transmitting and receiving. Transmit operation usesonly the 76 bytes at the start of a buffer; receive operation, all 80.

The transmit buffers are write only; the receive buffers, read only.

bit 15 ¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥¥

0x02007A0

0x020079F

Receive Buffer B (80 bytes)

0x0200750

0x020074F

Receive Buffer A (80 bytes)

0x0200700

0x02006FF

0x02006A0

0x020069F

Transmit Buffer B (80 bytes)

0x0200650

0x020064F

Transmit Buffer A (80 bytes)

0x0200600

Figure 10.11 PHS Communications Mode Data Buffers

FCS (CRC) Checking

PHS communications uses the following CRC polynomial for validating frame data integrity. CRC-32: G(χ )=1+ χ 1 + χ 2 + χ 4 + χ 5 + χ 7 + χ 8 + χ 10 + χ 11 + χ 12 + χ 16 + χ 22 + χ 23 + χ 26 + χ 32

Figure 10.12 shows the range of application.

Serial data

 

Serial data (608 bits)

CRC-32 (32 bits)

 

Input for CRC-32 calculation (608 bits)

Frame data (640 bits)

Figure 10.12 PHS Communications Mode FCS (CRC) Position

Output Port Control

For communications macro select(MCRS) register(D[1:0]/0x200000) setings other than 00-that is,HDLC, PDC,and PHS communications modes-the MOPORT3 and MOPORT2 bits in the communications block output port data register(D[3:0]/0x020000A) drive the RTS and DTR pins using negative logic.

Input Port Monitoring

The MIPORT[1:0] bits in the communications block input port data register (D[1:0]/0x020000C) track the input levels for the DSR and RI pins. Note that the block does not store these values internally.

In this mode as in others, setting the GOUTE bit in the communications block input port data register (D7/0x020000C) to "1" connects the RI input to the GOUT output pin.

Note: Bits in the communications block modem status register (0x020002A) also track the input levels for the DSR and RI pins as well as transitions for triggering interrupt requests with changes in pin states.

B-III-10-12

EPSON

S1C33210 FUNCTION PART