22

06/19/2000

GL600USB/GL600USB-A/GL600USB-B

Revision 1.3

Figure 4-5 Data Signal Rise and Fall Time

4.7.3

Serial Interface Engine (SIE)

The SIE manages data movement between the CPU and the transceiver. The SIE handles both transmit and

receive operations on the USB. It contains the logic used to manipulate the transceiver and the endpoint

registers.

The byte count buffer is loaded from TXCNT(TXCTL0<3~0>) during endpoint 0 transmit operations. This

same buffer is used for receive transactions to count the number of bytes received at endpoint 0 and, upon

the end of transaction, transfer the value t o RXCNT(RXCTL0<3~0>).

When transmitting, the SIE handles parallel-to-serial conversion, CRC generation, NRZI encoding, and bit

stuffing. When receiving, the SIE handles sync detection, packet identification, end-of-packet detection, bit

(un)stuffing, NRZI decoding, CRC validation, and serial-to-parallel conversion. Errors detected by the SIE

include bad CRC, timeout while waiting for EOP, and bit stuffing violations.

All USB devices are required to have an endpoint 0 that is used to initialize and manipulate the device.

Endpoint 0 provides access to the device’s configuration information and allows generic USB status and

control accesses. Endpoint 0 can receive and transmit data. Both receive and transmit data share the same

8-byte Endpoint 0 FIFO, FFDAT0. Received data may overwrite the data previously in the FIFO.

Endpoint 1 is of transmit only. This endpoint is used to transmit HID report data to host.

4.8

INSTRUCTION SET SUMMARY

4.8.1

Operand Field Descriptions

Field

Description

r

Register address

A

Accumulator

i

Immediate data

b

Bit address within a 8-bit register

4.8.2

Instruction Set

Mnemonic,

Operands

Description

Cycles

Flags

Affected

Arithmetic Operations

ADDAR r, A

Add r and A, r <- r + A

1

CA, HC, ZO

ADDAR A, r

Add A and r, A <- A + r

1

CA, HC, ZO

ADDAI i

Add A and i, A <- A + i

1

CA, HC, ZO

INCR r

Increment r, r <- r +1

1

ZO

INCR A, r

Increment r, A <- r + 1

1

ZO

INCRSZ r

Increment r, r <- r +1, skip if (r = 0)

1 or 2

INCRSZ A, r

Increment r, A <- r +1, skip if (A = 0)

1 or 2

SUBAR r, A

Subtract A from r, r <- r - A

1

CA, HC, ZO

SUBAR A, r

Subtract A from r, A <- r - A

1

CA, HC, ZO

SUBIA i

Subtract A from i, A <- i - A

1

CA, HC, ZO