Information

PIC18F2455/2550/4455/4550
DS80220J-page 6 © 2008 Microchip Technology Inc.
8. Module: A/D
The A/D offset is greater than the specified limit in
Table 28-28 of the Device Data Sheet. The
updated conditions and limits are shown in bold
text in Table 1.
Work around
Three work arounds exist.
1. Configure the A/D to use the V
REF+ and VREF-
pins for the voltage references. This is done by
setting the VCFG<1:0> bits (ADCON1<5:4>).
2. Perform a conversion on a known voltage
reference voltage and adjust the A/D result in
software.
3. Increase system clock speed to 48 MHz and
adjust A/D settings accordingly. Higher system
clock frequencies decrease offset error.
Date Codes that pertain to this issue:
All engineering and production devices.
TABLE 1: A/D CONVERTER CHARACTERISTICS: PIC18F2455/2550/4455/4550 (INDUSTRIAL)
PIC18LF2455/2550/4455/4550 (INDUSTRIAL)
9. Module: DC Characteristics (BOR)
The values for parameter D005 (VBOR) in
Section 28.1 “DC Characteristics” of the Device
Data Sheet, when the trip point for
BORV1:BORV0 = 11, are not applicable as the
device may reset below the minimum operating
voltage for the device.
Work around
None.
Date Codes that pertain to this issue:
All engineering and production devices.
10. Module: USB
When an IN endpoint is owned by USB SIE and
the UCON register PKTDIS bit is set, if a USB NAK
event occurs on the IN endpoint before the
PKTDIS bit is clear, then after the PKTDIS is clear,
the pending IN endpoint will send out more bytes
than expected. For example, if configured to send
out 8 bytes, the SIE would actually send out
12 bytes of data.
Work around
The PKTDIS bit is set when a USB control transfer
setup packet is received. Clear this bit as soon as
possible, and clear it before turning over any IN
endpoint ownership to the SIE.
In the distributed C18 version of the USB library,
the following change should be made:
File: usbctrltrf.c, version 1.0, dated 11/19/04
Function:
void USBCtrlEPServiceComplete(void)
Required Modification:
Move UCONbits.PKTDIS = 0, which is located
at the end of the function, to the start of the
function instead.
Date Codes that pertain to this issue:
All engineering and production devices.
Param
No.
Symbol Characteristic Min Typ Max Units Conditions
A06A E
OFF Offset Error — — <±2.0 LSb VREF = VREF+ and VREF-
A06 E
OFF Offset Error — — <±3.5 LSb VREF = VSS and VDD