PIC32MX575F256LT-80I/PT Microchip Technology, PIC32MX575F256LT-80I/PT Datasheet - Page 40

• Manufacturer Part Number: PIC32MX575F256LT-80I/PT
• Description: 256KB Flash, 64KB RAM, 80 MHz, USB, 1xCAN, 8 DMA 100 TQFP 12x12x1mm T/R
• Manufacturer: Microchip Technology
• Series: PIC® 32MXr

Specifications of PIC32MX575F256LT-80I/PT

• Core Processor: MIPS32® M4K™
• Core Size: 32-Bit
• Speed: 80MHz
• Connectivity: CAN, I²C, SPI, UART/USART, USB OTG
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 85
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 2.3 V ~ 3.6 V
• Data Converters: A/D 16x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-TFQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIC32MX
The formula to calculate for the checksum for a PIC32
device is provided in Equation 17-1.
EQUATION 17-1:
17.4
The following sections 17.4.1- 17.4.5 demonstrate a
checksum calculation for the PIC32MX360F512L
device using Equation 17-1 “Checksum Formula”.
The following assumptions are made for the purpose of
this checksum calculation example:
• Program Flash and Boot Flash are in the erased
• Device Configuration is in the default state of the
To begin, each item on the right-hand side of the equa-
tion (PF, BF, DCR, DIR) is individually calculated. After
those values have been derived, the final value of the
checksum can be determined.
17.4.1
The size of Program Flash is 512 KB, which equals
524288 bytes. Since the program Flash is assumed to
be in erased state, the value of “PF” is resolved through
the following calculation:
TABLE 17-3:
DS61145G-page 40
state (all bytes are 0xFF)
device (no configuration changes are made)
DCR
DIR
PF = 0xFF + 0xFF + … 524288 times
PF = 0x7F80000 (32-bit number)
MASK
MASK
Where,
PF = 32-bit summation of all bytes in Program Flash
BF = 32-bit summation of all bytes in Boot Flash, except device Configuration registers
DEVCFG0
DEVCFG1
DEVCFG2
DEVCFG3
Register
Example of Checksum Calculation
=
=
DEVCFGX
DEVID
CALCULATING FOR “PF” IN THE
CHECKSUM FORMULA
32-bit summation of bytes MASK
X
Σ
3
= mask value from Table 17-1
=
DCR CALCULATION EXAMPLE
32-bit summation of bytes MASK
= mask value from Table 17-1
0
CHECKSUM FORMULA
POR Default Value
0x7FFFFFFF
0xFFFFFFFF
0xFFFFFFFF
0xFFFFFFFF
Checksum
(
=
2′s complement PF
(
DEVID
Total of the 32-bit Summation of Bytes =
& DEVID
DEVCFGX
0x009FF7A7
0x0000FFFF
0x110FF00B
0x00070077
Mask
(
& DEVCFGx
)
+
17.4.2
The size of the Boot Flash is 12 KB, which equals
12288 bytes. However, the last 16 bytes are device
Configuration registers, which are treated separately.
Therefore, the number of bytes in boot Flash that we
consider in this step is 12272. Since the boot Flash is
assumed to be in erased state, the value of “BF” is
resolved through the following calculation:
17.4.3
Since the device Configuration registers are left in their
default state, the value of the appropriate DEVCFG
register – as read by the PIC32 core, its respective
mask value, the value derived from applying the mask,
and the 32-bit summation of bytes (all as shown in
Table 17-3) provide the total of the 32-bit summation of
bytes.
From Table 17-3, the value of “DCR” is:
BF
BF = 0xFF + 0xFF + … 12272 times
BF = 0x002FC010 (32-bit number)
DCR = 0x000005D4 (32-bit number)
+
DCR
POR Default Value &
)
CALCULATING FOR “BF” IN THE
CHECKSUM FORMULA
CALCULATING FOR “DCR” IN THE
CHECKSUM FORMULA
0x110FF00B
0x009FF7A7
0x0000FFFF
0x00070077
+
DIR
Mask
)
© 2010 Microchip Technology Inc.
32-Bit Summation of
0x0000023D
0x000001FE
0x000005D4
0x0000011B
0x0000007E
Bytes