S1D13704 Epson Electronics America, Inc., S1D13704 Datasheet - Page 486

• Manufacturer Part Number: S1D13704
• Description: LCD Controller
• Manufacturer: Epson Electronics America, Inc.

Page 10
3.2 Generic #2 Interface Mode
S1D13704
X26A-G-013-02
Note
Note
Generic #2 Host Bus Interface is a general, non-processor specific interface mode on the
S1D13704 that is ideally suited to interface to an 8-bit processor bus.
The interface requires the following signals:
• BUSCLK is a clock input which synchronizes transfers between the host CPU and the
• The address inputs AB0 through AB15, and the data bus DB0 through DB15, connect
• Chip Select (CS#) is driven by decoding the high-order address lines to select the proper
• BHE# (WE1#) is the high byte enable for both read and write cycles.
• WE0# is the enable signal for a write access, to be driven low when the host CPU is
• RD# is the read enable for the S1D13704, to be driven low when the host CPU is
• WAIT# is a signal which is output from the S1D13704 to the host CPU that indicates
• The Bus Status (BS#) and Read/Write (RD/WR#) signals are not used in the bus inter-
S1D13704. It is separate from the input clock (CLKI) and is typically driven by the host
CPU system clock. If the host CPU bus does not provide this clock, an asynchronous
clock can be provided.
directly to the CPU address and data bus, respectively. On 32-bit big endian architec-
tures such as the Power PC, the data bus would connect to the high-order data lines; on
little endian hosts, or 16-bit big endian hosts, they would connect to the low-order data
lines. The hardware engineer must ensure that CNF3 selects the proper endian mode
upon reset.
In an 8-bit environment D[7:0] must also be connected to D[15:8] respectively
(see Figure 4-1: “Typical Implementation of an 8-bit Processor to the S1D13704 Gener-
ic #2 Interface” )
memory address space.
In an 8-bit environment, this signal is driven by inverting address line A0 thus indicating
that odd addresses are to be R/W on the high byte of the data bus.
writing the 13704 memory or registers.
reading data from the S1D13704.
when data is ready (read cycle) or accepted (write cycle) on the host bus. Since host
CPU accesses to the S1D13704 may occur asynchronously to the display update, it is
possible that contention may occur in accessing the 13704 internal registers and/or
refresh memory. The WAIT# line resolves these contentions by forcing the host to wait
until the resource arbitration is complete. This signal is active low and may need to be
inverted if the host CPU wait state signal is active high.
face for Generic #2 mode. However, BS# is used to configure the S1D13704 for
Generic #2 mode and should be tied high (connected to IO V
be tied high.
Epson Research and Development
DD
Interfacing to an 8-bit Processor
). RD/WR# should also
Vancouver Design Center
Issue Date: 01/02/12