Information

 2009 Microchip Technology Inc. DS80304D-page 1
PIC18F2420/2520/4420/4520
The PIC18F2420/2520/4420/4520 Rev. B3 parts you
have received conform functionally to the Device Data
Sheet (DS39631E), except for the anomalies
described below. Any Data Sheet Clarification issues
related to the PIC18F2420/2520/4420/4520 will be
reported in a separate Data Sheet errata. Please check
the Microchip web site for any existing issues.
The following silicon errata apply only to
PIC18F2420/2520/4420/4520 devices with these
Device/Revision IDs:
All of the issues listed here will be addressed in future
revisions of the PIC18F2420/2520/4420/4520 silicon.
1. Module: MSSP
In SPI Slave mode with slave select enabled
(SSPM<3:0> = 0100), the minimum time between
the falling edge of the SS pin and first SCK edge
is greater than specified in parameter 70 in
Table 26-16 and Table 26-17 of the above
referenced data sheet.
The updated specification is shown in bold in
Table 1.
Work around
None.
Date Codes that pertain to this issue:
All engineering and production devices.
2. Module: MSSP (SPI Mode)
When the SPI is using Timer2/2 as the clock
source, a shorter than expected SCK pulse may
occur on the first bit of the transmitted/received
data (Figure 1).
FIGURE 1: SCK PULSE VARIATION
USING TIMER2/2
Work around
To avoid producing the short pulse, turn off Timer2
and clear the TMR2 register, load the SSPBUF
with the data to transmit and then turn Timer2 back
on. Refer to Example 1 for sample code.
EXAMPLE 1: AVOIDING THE INITIAL
SHORT SCK PULSE
Date Codes that pertain to this issue:
All engineering and production devices.
TABLE 1: EXAMPLE SPI MODE REQUIREMENTS (SLAVE MODE TIMING)
Part Number Device ID Revision ID
PIC18F2420 0001 0001 010 0 0110
PIC18F2520 0001 0001 000 0 0110
PIC18F4420 0001 0000 110 0 0110
PIC18F4520 0001 0000 100 0 0110
The Device IDs (DEVID1 and DEVID2) are located at
addresses 3FFFFEh:3FFFFFh in the device’s
configuration space. They are shown in hexadecimal
in the format “DEVID2 DEVID1”.
SDO
SCK
Write SSPBUF
bit 0 = 1 bit 1 = 0 bit 2 = 1 . . . .
LOOP BTFSSSSPSTAT, BF ;Data received?
;(Xmit complete?)
BRA LOOP ;No
MOVFSSPBUF, W ;W = SSPBUF
MOVWFRXDATA ;Save in user RAM
MOVFTXDATA, W ;W = TXDATA
BCF T2CON, TMR2ON;Timer2 off
CLRFTMR2 ;Clear Timer2
MOVWFSSPBUF ;Xmit New data
BSF T2CON, TMR2ON;Timer2 on
Param
No.
Symbol Characteristic Min Max Units Conditions
70 T
SSL2SCH,
T
SSL2SCL
SS
 to SCK  or SCK  Input 3TCY —ns
PIC18F2420/2520/4420/4520 Rev. B3 Silicon Errata