Ricoh R5C841 - Manual (Page 48)

R5C841 PCI-CardBus/IEEE 1394/SD Card/Memory Stick/xD/ExpressCard Data Sheet
12345  2004 R EV .1.10 4-23
4.21.5 LED Output Selection
All LED can be output to LED0#/LED1#. The LED for the 1394 is output by setting Config
(Func.1) 9Eh bit [4:3] to “11b”, the LED for the SD Card is output by setting Config (Func.2) F8h
bit [7:6] to “11b”, the LED for the Memory Stick is output by setting Config (Func.3) F8h bit [7:6]
to ”11b”, and the LED for the xD Picture Card is output by setting Config (Func.4) F8h bit [7:6]
to ”11b”.
Also, the LED for the IEEE1394 is output to LED2# by setting Config (Func.0) B0h bit6 to “0b”.
4.22 1394 Cable Interface
The R5C841 builds in 2 ports of 1394 Cable interface that support the transmission speed of
400/200/100Mbps compliant with the IEEE1394a-2000 standard.
4.22.1 Cable Interface Circuit
AVCC_PHY3V
ICD
ICD
R5C841 Boad A Cable Boad B
Connect Detect
Connect_Detect
TpBias Disable TpBias_Disable
TPBIAS*
0.33uF
TPAP*
TPAP TPAP
Driver Driver
Strb_Tx Strb_TX
Strb_Enable
Strb_Enable
Receipt Signals TPAN* TPAN TPAN Receipt Signals
Data_Rx 56ohm ±3% Data_Rx
Arb_A_Rx etc Arb_A_Rx etc
TPBP*
Driver Driver
Data_Tx TPBP TPBP Data_Tx
Data_Enable
Data_Enable
Receipt Signals
TPBN* TPBN TPBN Receipt Signals
Strb_Rx 56ohm ±3% Strb_Rx
Arb_B_Rx etc 270pF Arv_B_Rx etc
5.1kohm ±5%
AGND
System A System B
* means a port number in this figure.
(Example: TPBIAS* → TPBIAS0 or TPBIAS1)
Each port consists of two twist-pairs; TPA and TPB. The TPA and the TPB are used in order to
monitor transmission/reception of a control signal (Arbitration signal) and data, and the state of a
cable line (the insert of a cable).
It is necessary for the TPA and the TPB to be connected to a termination of 55 Ω resistances
according to the cable impedance. This termination resistance should be arranged near the
R5C841. On TPA side, TPBIAS should be placed to the center node of the termination resistance
in order to set up a cable’s common-mode DC potential. A capacitor of 0.33µF for decoupling
should be connected to the TPBIAS. On TPB side, a termination of 5.1k Ω and a capacitor of
270pF should be connected to between the center node of the termination resistance and AGND.
See the application manual for the substrate layout.