Atm/Pos Interface - NEC UPD98413 User Manual

2.2.2 ATM/POS Interface

The ATM/POS interface transfers ATM cells or POS packets to and from an ATM/POS device.
ATM Interface
Pin Name Serial No.
RXCLK
RXDATA[31:0]
RXSOC
RXENB_B
RXPRTY
RXCLAV0-3
RXADDR[1:0]
CHAPTER 2 PIN FUNCTION
Address No. I/O Level
I
LVTTL
O
LVTTL
O
LVTTL
I
LVTTL
O
LVTTL
O
LVTTL
I
LVTTL
PRELIMINARY
Function
Receive clock input.
This pin inputs the clock, up to 104 MHz, used to transfer
receive data.
Receive data output.
These pins form a 32-bit data bus through which receives
cell data is output to the ATM device. The data on this bus
is updated at the rising edge of RXCLK. RXDATA31 is the
MSB. RXDATA0 is the LSB.
Receive cell start position signal output.
This pin goes high during the clock cycle in which the first
byte of the receive cell is output to RXDATA, to post
notification to the ATM device.
Receive enable signal input.
The ATM device enables or disables the receive cell data
output by the µPD98413. The µPD98413 samples
RXENB_B at the rising edge of RXCLK. When it detects
the low level of RXENB_B, it updates the output of RSOC
and RXDATA starting from the next clock cycle, and then
transfers the receive cell data. If RXENB_B is high, the
µPD98413 stops the output of RSOC and RXDATA,
starting from the next clock cycle.
Receive data path parity.
This pin generates an odd parity bit for the output data on
RXDATA and outputs it from RXPRTY. The parity bit is
always output.
The parity bit to be generated can be changed to even parity
depending on the setting of the PARM bit of MDAPIR
register.
Receive cell available.
µ
The PD98413 drives RXCLAV high if one or more cells of
receive data to be transferred exists in the receive FIFO, to
post notification to the ATM device. RXCLAV is held high if
one or more cells of valid data exists in the receive FIFO at
the 2 clock cycle or later after the start of output of the cell;
otherwise, RXCLAV goes low. RXCLAV0 corresponds to
PORT0, while RXCLAV3 corresponds to PORT3.
Receive PHY address input.
These pins are used to input a port address for requesting
data output.
NEC confidential and Proprietary
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