PIC18F24J10-I/SS Microchip Technology Inc., PIC18F24J10-I/SS Datasheet - Page 231

• Manufacturer Part Number: PIC18F24J10-I/SS
• Description: Microcontroller; 16 KB Flash; 1024 RAM; 0 EEPROM; 21 I/O; 28-Pin-SSOP
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F24J10-I/SS

• A/d Inputs: 10-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 21
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SSOP
• Programmable Memory: 16K Bytes
• Ram Size: 1K Bytes
• Speed: 40 MHz
• Timers: 1-8-bit, 2-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

20.0
PIC18F45J10 family devices include several features
intended to maximize reliability and minimize cost
through elimination of external components. These are:
• Oscillator Selection
• Resets:
• Interrupts
• Watchdog Timer (WDT)
• Fail-Safe Clock Monitor
• Two-Speed Start-up
• Code Protection
• In-Circuit Serial Programming
The oscillator can be configured for the application
depending on frequency, power, accuracy and cost. All
of the options are discussed in detail in Section 2.0
“Oscillator Configurations”.
A complete discussion of device Resets and interrupts
is available in previous sections of this data sheet.
In addition to their Power-up and Oscillator Start-up
Timers provided for Resets, the PIC18F45J10 family of
devices have a configurable Watchdog Timer which is
controlled in software.
The inclusion of an internal RC oscillator also provides
the additional benefits of a Fail-Safe Clock Monitor
(FSCM) and Two-Speed Start-up. FSCM provides for
background monitoring of the peripheral clock and
automatic switchover in the event of its failure.
Two-Speed Start-up enables code to be executed
almost immediately on start-up, while the primary clock
source completes its start-up delays.
All of these features are enabled and configured by
setting the appropriate Configuration register bits.
20.1
The configuration bits can be programmed (read as ‘0’)
or left unprogrammed (read as ‘1’) to select various
device configurations. These bits are mapped starting
at program memory location 300000h. A complete list
is shown in Table 20-1. A detailed explanation of the
various bit functions is provided in Register 20-1
through Register 20-6.
Note that address 300000h is beyond the user program
memory space. In fact, it belongs to the configuration
memory space (300000h-3FFFFFh) which can only be
accessed using table reads and table writes.
© 2006 Microchip Technology Inc.
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
SPECIAL FEATURES OF THE
CPU
Configuration Bits
Preliminary
PIC18F45J10 FAMILY
20.1.1
Unlike most PIC18 microcontrollers, devices of the
PIC18F45J10 family do not use persistent memory
registers to store configuration information. The config-
uration bytes are implemented as volatile memory
which means that configuration data must be
programmed each time the device is powered up.
Configuration data is stored in the four words at the top
of the on-chip program memory space, known as the
Flash Configuration Words. It is stored in program
memory in the same order shown in Table 20-1, with
CONFIG1L at the lowest address and CONFIG3H at
the highest. The data is automatically loaded in the
proper Configuration registers during device power-up.
When creating applications for these devices, users
should always specifically allocate the location of the
Flash Configuration Word for configuration data; this is
to make certain that program code is not stored in this
address when the code is compiled.
The volatile memory cells used for the configuration
bits always reset to ‘1’ on Power-on Resets. For all
other type of Reset events, the previously programmed
values are maintained and used without reloading from
program memory.
The four Most Significant bits of CONFIG1H,
CONFIG2H and CONFIG3H in program memory
should also be ‘1111’. This makes these Configuration
Words appear to be NOP instructions in the remote
event that their locations are ever executed by
accident. Since configuration bits are not implemented
in the corresponding locations, writing ‘1’s to these
locations has no effect on device operation.
To prevent inadvertent configuration changes during
code execution, all programmable configuration bits
are write-once. After a bit is initially programmed during
a power cycle, it cannot be written to again. Changing
a device configuration requires a device Reset.
CONSIDERATIONS FOR
CONFIGURING THE PIC18F45J10
FAMILY DEVICES
DS39682B-page 229