PIC18F8525-I/PT Microchip Technology, PIC18F8525-I/PT Datasheet - Page 75

• Manufacturer Part Number: PIC18F8525-I/PT
• Description: IC PIC MCU FLASH 24KX16 80TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F8525-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Size: 48KB (24K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 3.75K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 16x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TFQFP
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 3840 B
• Interface Type: MSSP, SPI, I2C, EUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 69
• Number Of Timers: 2 x 8 bit
• Operating Supply Voltage: 4.2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DV164136, DM163032
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 16 bit
• For Use With: XLT80PT3 - SOCKET TRAN ICE 80MQFP/TQFPAC164320 - MODULE SKT MPLAB PM3 80TQFPAC174011 - MODULE SKT PROMATEII 80TQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.2
The external memory interface implemented in
PIC18F8525/8621 devices operates only in 16-bit
mode. The mode selection is not software configurable
but is programmed via the configuration bits.
The WM1:WM0 bits in the MEMCON register
determine three types of connections in 16-bit mode.
They are referred to as:
• 16-bit Byte Write
• 16-bit Word Write
• 16-bit Byte Select
These three different configurations allow the designer
maximum flexibility in using 8-bit and 16-bit memory
devices.
For all 16-bit modes, the Address Latch Enable (ALE)
pin indicates that the address bits, A15:A0, are
available on the external memory interface bus.
Following the address latch, the Output Enable signal
(OE) will enable both bytes of program memory at once
to form a 16-bit instruction word. The Chip Enable
signal (CE) is active at any time that the microcontroller
accesses external memory, whether reading or writing;
it is inactive (asserted high) whenever the device is in
Sleep mode.
FIGURE 6-1:
 2005 Microchip Technology Inc.
Note 1: This signal only applies to table writes. See Section 5.1 “Table Reads and Table Writes”.
16-Bit Mode
PIC18F8X2X
AD<15:8>
A<19:16>
AD<7:0>
WRH
WRL
ALE
CE
OE
16-BIT BYTE WRITE MODE EXAMPLE
PIC18F6525/6621/8525/8621
373
373
D<7:0>
A<19:0>
D<15:8>
In Byte Select mode, JEDEC standard Flash memories
will require BA0 for the byte address line and one I/O
line, to select between Byte and Word mode. The other
16-bit modes do not need BA0. JEDEC standard static
RAM memories will use the UB or LB signals for byte
selection.
6.2.1
Figure 6-1 shows an example of 16-bit Byte Write mode
for PIC18F8525/8621 devices. This mode is used for
two separate 8-bit memories connected for 16-bit
operation. This generally includes basic EPROM and
Flash devices. It allows table writes to byte-wide external
memories.
During a TBLWT instruction cycle, the TABLAT data is
presented on the upper and lower bytes of the
AD15:AD0 bus. The appropriate WRH or WRL control
line is strobed on the LSb of the TBLPTR.
16-BIT BYTE WRITE MODE
A<x:0>
D<7:0>
CE
OE
(MSB)
WR
(1)
Address Bus
Data Bus
Control Lines
D<7:0>
DS39612B-page 73
A<x:0>
D<7:0>
CE
OE
(LSB)
WR
(1)