RCVDL56DPFL/SP, RCV56DPFL/SP, and RCV336DPFL/SP Designer’s Guide
2-8
1119
Table 2-2. MDP Signal Definitions (Cont'd)
Label
I/O Type
Signal Name/Description
PARALLEL HOST INTERFACE
Address, data, control, and interrupt hardware interface signals allow MDP connection to an 8086-compatible microprocessor bus. With the
addition of external logic, the interface can be made compatible with a wide variety of other microprocessors such as the 6502, 8086 or 68000.
The microprocessor interface allows a microprocessor to change MDP configuration, read or write channel and diagnostic data, and supervise
MDP operation by writing control bits and reading status bits.
D0–D7
IA/OB
Data Lines. Eight bidirectional data lines (D0–D7) provide parallel transfer of data between the host and the MDP.
The most significant bit is D7. Data direction is controlled by the Read Enable and Write Enable signals.
RS0–RS4
IA
Register Select Lines. The five active high register select lines (RS0–RS4) address interface memory registers
within the MDP interface memory. These lines are typically connected to the five least significant lines (A0–A4) of
the address bus.
The MDP decodes RS0 through RS4 to address one of 32 internal interface memory registers (00–1F). The most
significant address bit is RS4, while the least significant address bit is RS0. The selected register can be read from
or written into via the 8-bit parallel data bus (D0–D7). The most significant data bit is D7, while the least significant
data bit is D0.
~CS
IA
Chip Select. ~CS selects the MDP for microprocessor bus operation. ~CS is typically generated by decoding host
address bus lines.
~READ
IA
Read Enable. During a read cycle (~READ asserted), data from the selected interface memory register is gated
onto the data bus by means of three-state drivers in the MDP. These drivers force the data lines high for a one bit,
or low for a zero bit. When not being read, the three-state drivers assume their high-impedance (off) state.
~WRITE
IA
Write Enable. During a write cycle (~WRITE asserted), data from the data bus is copied into the selected MDP
interface memory register, with high and low bus levels representing one and zero bit states, respectively.
IRQ
OA
Interrupt Request. The MDP IRQ output may be connected to the host processor interrupt request input in order
to interrupt host program execution for immediate MDP service. The IRQ output can be enabled in the MDP
interface memory to indicate immediate change of conditions. The use of IRQ is optional depending upon MDP
application. The IRQ output is driven by a TTL-compatible CMOS driver.
Summary of Contents for RC336DPFL
Page 193: ...INSIDE BACK COVER NOTES ...