PIC18F6520-I/PT Microchip Technology Inc., PIC18F6520-I/PT Datasheet - Page 76

• Manufacturer Part Number: PIC18F6520-I/PT
• Description: 64 PIN, 32 KB FLASH, 2048 RAM, 52 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F6520-I/PT

• A/d Inputs: 12-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 1024 Bytes
• Input Output: 52
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 64-pin TQFP
• Programmable Memory: 32K Bytes
• Ram Size: 2K Bytes
• Speed: 40 MHz
• Timers: 2-8 bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC18F6520/8520/6620/8620/6720/8720
6.2.2
Figure 6-2 shows an example of 16-bit Word Write
mode for PIC18F8X20 devices. This mode is used for
word-wide memories, which includes some of the
EPROM and Flash type memories. This mode allows
opcode fetches and table reads from all forms of 16-bit
memory and table writes to any type of word-wide
external memories. This method makes a distinction
between TBLWT cycles to even or odd addresses.
During
(TBLPTR<0> = 0), the TABLAT data is transferred to a
holding latch and the external address data bus is
tri-stated for the data portion of the bus cycle. No write
signals are activated.
FIGURE 6-2:
DS39609B-page 74
Note 1: This signal only applies to table writes. See Section 5.1 “Table Reads and Table Writes”.
a
PIC18F8X20
16-BIT WORD WRITE MODE
TBLWT
AD<15:8>
A<19:16>
AD<7:0>
cycle
16-BIT WORD WRITE MODE EXAMPLE
WRH
ALE
CE
OE
to
an
even
address
373
373
During
(TBLPTR<0> = 1), the TABLAT data is presented on
the upper byte of the AD15:AD0 bus. The contents of
the holding latch are presented on the lower byte of the
AD15:AD0 bus.
The WRH signal is strobed for each write cycle; the
WRL pin is unused. The signal on the BA0 pin indicates
the LSb of TBLPTR, but it is left unconnected. Instead,
the UB and LB signals are active to select both bytes.
The obvious limitation to this method is that the table
write must be done in pairs on a specific word boundary
to correctly write a word location.
A<20:1>
D<15:0>
a
TBLWT
Address Bus
Data Bus
Control Lines
D<15:0>
A<x:0>
cycle
 2004 Microchip Technology Inc.
CE
EPROM Memory
to
OE
JEDEC Word
an
WR
odd
(1)
address