
21145
Preliminary
 Datasheet
11
mii/sym_txd<3:0>
O
148, 149, 
150, 151
119, 120, 
121, 122
Four parallel transmit data lines.  This data is 
synchronized to the assertion of the mii_tclk signal and is 
latched by the external PHY on the rising edge of the 
mii_tclk signal.
mii_txen/sym_txd<4>
O
152
123
In MII mode, this pin functions as transmit enable. It 
indicates that a transmission is active on the MII port to 
an external PHY device.
In SYM mode, this pin functions as transmit data. This 
line along with the four data transmit lines (sym_txd<3:0>) 
provides five parallel data lines in symbol form. The data 
is synchronized to the rising edge of the sym_tclk signal.
par
I/O
74
59
Parity is calculated by the 21145 as an even parity bit for 
the 32-bit ad and 4-bit c_be_l lines.
During address and data phases, parity is calculated on 
all the ad and c_be_l lines whether or not any of these 
lines carry meaningful information.
pci_clk
I
27
19
The clock provides the timing for the 21145 related PCI 
bus transactions. All the bus signals are sampled on the 
rising edge of pci_clk. The supported clock frequency 
range is 20 MHz to 33 MHz.
perr_l
I/O
72
57
Parity error asserts when a data parity error is detected.
When the 21145 is the bus master and a parity error is 
detected, the 21145 asserts both CSR5 bit 13 (fatal bus 
error) and CFCS bit 24 (data parity report). Next, it 
completes the current data burst transaction, then stops 
operation. After the host clears the system error via 
CSR5<13>, the 21145 continues its operation.
The 21145 asserts perr_l when a data parity error is 
detected in either a master-read or a slave-write 
operation.
req_l
O
30
22
Bus request is asserted by the 21145 to indicate to the 
bus arbiter that it wants to use the bus.
rst_l
I 
22
16
Resets the 21145 to its initial state. This signal must be 
asserted for at least 10 active PCI clock cycles. When in 
the reset state, all PCI output pins are put into tristate and 
all PCI O/D signals are floated.
rsv 
—
15, 16, 17, 
63, 145, 170, 
171, 172
88, 89, 90, 
92, 93, 96, 
97, 98, 99, 
138, 139, 
140
Reserved. These pins should remain unconnected.
rsv_vdd
I
55
NA
Must be connected to Vdd for proper operation.
serr_l
O/D  
73
58
If an address parity error is detected and CFCS bit 8 
(serr_l enable) is enabled, 21145 asserts both serr_l 
(system error) and CFCS bit 30 (signal system error).
When an address parity error is detected, system error 
asserts two clocks after the failing address.
sr_ck
O
138
114
Serial ROM clock signal.  This pin provides a serial  clock 
output for the serial ROM.  
sr_cs
O
139
115
Serial ROM chip-select signal. This pin provides a chip 
select for the serial ROM.   
Table 1. Functional Description of 21145 Signals (Sheet 6 of 8)
Signal
Type
Pin 
Number, 
176-pin
Pin 
Number, 
144-pin
Description