peb3456 Infineon Technologies Corporation, peb3456 Datasheet - Page 153

• Manufacturer Part Number: peb3456
• Description: Channelized T3 Termination With Ds3 Framer, M13 Multiplexer, T1/ E1 Framers And 256 Channel Hdlc/ppp Controller
• Manufacturer: Infineon Technologies Corporation

(1) in
long as the local bus latency timer is not expired. A read/write transaction begins when
the TE3-CHATT places a valid address on the address bus, sets the LBHE signal which
5.3.1
5.3.1.1
In Intel slave mode the bus interface supports 16-bit transactions in demultiplexed bus
operation. It uses the local bus port pins LA(12:1) for the 16 bit address and the local bus
port pins LD(15:0) for 16 bit data. A read/write access is initiated by placing an address
on the address bus and asserting LCS0 (Figure 5-5). The external processor then
activates the respective command signal (LRD, LWR). Data is driven onto the data bus
either by the TE3-CHATT (for read cycles) or by the external processor (for write cycles).
After a period of time, which is determined by the access time to the internal registers
valid data is placed on the bus, which is indicated by asserting the active low signal
LRDY.
Note: LCS0 need not be deasserted between two subsequent cycles to the same
Read cycles
Input data can be latched and the command signal can be deactivated now. This causes
the TE3-CHATT to remove its data from the data bus which is then tri-stated again.
LRDY is driven high and will be tri-stated as soon as LCS0 is deasserted.
Write cycles
The command signal can be deactivated now. If a subsequent bus cycle is required, the
external processor can place the respective address on the address bus.
5.3.1.2
A read/write access from the PCI bus to the 16 bit demultiplexed local bus is initiated by
accessing the PCI memory space base which is controlled by the base address
register 2. Each valid read or write access to this base address triggers the local bus
master interface which in turn starts arbitration for the local bus by asserting LHOLD (see
asserted) it starts the local bus latency timer and begins a read/write transaction as the
bus master. The signal LHOLD remains asserted while a transaction is in progress or as
indicates a 8- or 16-bit bus access and asserts the chip select signals LCS1 and/or
LCS2. Then the TE3-CHATT activates the respective command signals (LRD, LWR).
Data is driven onto the data bus either by the TE3-CHATT (for write cycles) or by the
accessed device (for read cycles).
A transaction is finished on the local bus when the external device asserts LRDY (ready
controlled bus cycles) or when the internal wait state timer expires.
Data Sheet
device.
Figure
Intel Mode
Slave Mode
Master Mode
5-6). As soon as the TE3-CHATT gets access to the local bus (LHLDA
153
Interface Description
PEB 3456 E
05.2001