W78E516B-24 Winbond, W78E516B-24 Datasheet - Page 4

• Manufacturer Part Number: W78E516B-24
• Description: 8-BIT MICROCONTROLLER
• Manufacturer: Winbond

BLOCK DIAGRAM
FUNCTIONAL DESCRIPTION
The W78E516B architecture consists of a core controller surrounded by various registers, four
general purpose I/O ports, one special purpose programmable 4-bits I/O port, 512 bytes of RAM,
three timer/counters, a serial port and an internal 74373 latch and 74244 buffer which can be
switched to port2. The processor supports 111 different opcodes and references both a 64K program
address space and a 64K data storage space.
RAM
The internal data RAM in the W78E516B is 512 bytes. It is divided into two banks: 256 bytes of
scratchpad RAM and 256 bytes of AUX-RAM. These RAMs are addressed by different ways.
P1.0
P1.7
RAM 0H 127H can be addressed directly and indirectly as the same as in 8051. Address pointers
are R0 and R1 of the selected register bank.
RAM 128H 255H can only be addressed indirectly as the same as in 8051. Address pointers are
R0, R1 of the selected registers bank.
P3.0
P3.7
P4.0
P4.3
Port
1
Port
Port
3
4
Interrupt
UART
Port 1
Port 3
Port 4
Latch
Timer
Timer
Timer
Latch
Latch
2
0
1
XTAL1
Oscillator
XTAL2
PSW
Bus & Clock
Sequencer
Instruction
Controller
Decoder
ALE
ACC
&
T1
PSEN
ALU
Reset Block
RAM & SFR
SFR RAM
Address
512 bytes
- 4 -
RST
T2
B
Pointer
Stack
Power control
VCC
Vss
Temp Reg.
Addr. Reg.
Incrementor
DPTR
MTP-ROM
MTP-ROM
PC
Port 0
Latch
64KB
4KB
Port 2
Latch
W78E516B
Port
Port
2
0
P0.0
P2.0
P2.7
P0.7