NEC UPD98413 User Manual page 129

(1) Transmit interface
The transmit interface uses the signals defined below.
TFCLK Transmit FIFO write clock.
TFCLK is used to synchronize data transfer transactions between the µPD98413 and the POS
(input):
device. TFCLK cycles at a rate up to 104MHz.
TDAT[31:0]
Transmit packet data bus.
(input): TDAT[31:0] carries the transmit packet data and the in-band port address. The TDAT bus is
considered valid only when TENB_B is asserted. TDAT31 is the MSB, TDAT0 is the LSB.
TSOP
Transmit start of packet.
(input):
TSOP is used to delineate the packet boundaries on the TDAT bus. When TSOP is high, the
start of the packet is present on the TDAT bus. TSOP is considered valid only when TENB_B
is asserted.
TENB_B Transmit write enable.
(input):
TENB_B is used to control the flow of data to the transmit FIFO. When TENB_B is high, the
TDAT, TMOD, TSOP, TEOP, and TERR signals are invalid. TSX is valid when TENB_B is
high.
When TENB_B is low, the TDAT, TMOD, TSOP, TEOP, and TERR signals are valid. TSX is
invalid when TENB_B is low.
TPRTY
Transmit bus parity.
(input): TPRTY indicates the parity calculated over the TDAT bus. TPRTY is considered valid only
when TENB_B or TSX is asserted.
The µPD98413 supports the odd or even parity. When the µPD98413 detects a parity error,
the µPD98413 indicates it by the register. Even if a parity error is detected, data transfer
continues without being affected.
TEOP Transmit end of packet.
(input): TEOP is used to delineate the packet boundaries on the TDAT bus. When TEOP is high, the
data on TDAT is assumed to be the end of a packet, and the valid bytes of the last word are
indicated by TMOD[1:0]. TEOP is considered valid only when TENB_B is asserted.
TMOD[1:0] Transmit word modulo.
(input): TMOD[1:0] indicates the valid bytes of the transmit data on TDAT[31:0]. When TEOP is
asserted, the valid bytes on TDAT[31:0] are specified by TMOD[1:0] below.
00: TDAT[31:0] is valid.
01: TDAT[31:8] is valid.
10: TDAT[31:16] is valid.
11: TDAT[31:24] is valid.
TMOD[1:0] is considered valid only when TENB_B is asserted.
CHAPTER 4 INTERFACES
PRELIMINARY
NEC confidential and Proprietary
129