Page 14
Epson Research and Development
Vancouver Design Center
3.2 PowerPC Host Bus Interface Signals
The S1D13506 PowerPC host bus interface is designed to support processors which
interface the S1D13506 through the PowerPC bus.
The S1D13506 PowerPC host bus interface requires the following signals:
• BUSCLK is a clock input which is required by the S1D13506 host bus interface. It is
separate from the input clock (CLKI) and is typically driven by the host CPU system
clock.
• The address inputs AB[20:0], and the data bus DB[15:0], connect directly to the
PowerPC bus address (A[11:31]) and data bus (D[0:15]), respectively. MD4 must be set
to select the proper endian mode upon reset.
• M/R# (memory/register) selects between memory or register access. It may be
connected to an address line, allowing system address A10 to be connected to the M/R#
line.
• Chip Select (CS#) must be driven low whenever the S1D13506 is accessed by the
PowerPC bus.
• RD/WR# connects to RD/WR which indicates whether a read or a write access is being
performed on the S1D13506.
• WE1# connects to BI (burst inhibit signal). WE1# is output by the S1D13506 to indicate
whether the S1D13506 is able to perform burst accesses.
• WE0# and RD# connect to TSIZ1 and TSIZ0 (high and low byte enable signals). These
signals must be driven by the PowerPC bus to indicate the size of the transfer taking
place on the bus.
• WAIT# connects to TA and is output from the S1D13506 to indicate the PowerPC bus
must wait until data is ready (read cycle) or accepted (write cycle) on the host bus. Since
PowerPC bus accesses to the S1D13506 may occur asynchronously to the display
update, it is possible that contention may occur while accessing the S1D13506 internal
registers and/or display buffer. The WAIT# line resolves these contentions by forcing
the host to wait until resource arbitration is complete.
• The Bus Start (BS#) signal connects to TS (the transfer start signal).
S1D13506
X25B-G-008-03
Interfacing to the Motorola MPC821 Microprocessor
Issue Date: 01/02/08
EPSON [ EPSON COMPANY ]
