Information

ManualsBrandsMICROCHIP TECHNOLOGY ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller SPDIP 28 8-Bit 24 MHz I/O number 22

 2002 Microchip Technology Inc. DS80114C-page 1

PIC16C745/765

The PIC16C745/765 (Rev. A1) parts you have received

conform functionally to the PIC16C745/765 Data Sheet

(DS41124C), except for the anomalies described

below.

All significant issues listed here are addressed by Rev.

A2 of the PIC16C745/765 silicon.

1. Module: USB Transceiver

The first bit in the sync pattern during Microcontroller-

to-host transactions is elongated by approximately

100 ns (see Figure 1). According to Section 7.1.11 of

the USB Specification, Version 1.1, the bit period for a

low speed device can vary 1.5% from 667 ns. This

means the average bit length can vary from 657 ns to

676 ns. Section 7.1.13.1 states, “For low speed trans-

missions, the jitter time for any consecutive differential

data transitions must be within ±25 ns and within

±10 ns for any set of paired differential data

transitions.”

The initial bit from the PIC16C745/765, at approxi-

mately 772 ns in length, violates the consecutive transi-

tion jitter specification by 71 ns to 90 ns, depending on

the actual data rate. It violates the paired data transition

jitter specification by 82 ns to 120 ns, depending on the

actual data rate. Devices based on the PIC16C745/765

are likely to fail the USB Implementer’s Forum Compli-

ance Test due to the jitter violation. However, the elon-

gated bit does not affect the reliability of USB

transactions between current USB host controllers and

the PIC16C745/765. All packets are communicated

successfully between microcontroller and host.

Work Around

No work around available.

FIGURE 1: USB TRANSCEIVER TIMING

Note: The silicon revision of a specific compo-

nent is identified by its manufacture date

code: YYWW. YY is the year of manufac-

ture and WW is the specific work week. All

material with a date code of 0230 or earlier

is Rev. A1 silicon and subject to this Errata

document. Components with a date code

later than 0230 will be Rev. A2 silicon and

will be covered by a separate Errata docu-

ment. For additional information concern-

ing date codes, refer to the packaging

information section of the PIC16C745/765

Data Sheet (DS41124C)

Note: USB-IF certification is necessary only if

use of the USB logo is desired.

D -

D +

SOP

First Bit

of Packet

772 ns 667 ns 667 ns . . .

PIC16C745/765 Rev. A1 Silicon/Data Sheet Errata

Summary of content (6 pages)

PAGE 1
PIC16C745/765 PIC16C745/765 Rev. A1 Silicon/Data Sheet Errata The PIC16C745/765 (Rev. A1) parts you have received conform functionally to the PIC16C745/765 Data Sheet (DS41124C), except for the anomalies described below. Note: The silicon revision of a specific component is identified by its manufacture date code: YYWW. YY is the year of manufacture and WW is the specific work week. All material with a date code of 0230 or earlier is Rev. A1 silicon and subject to this Errata document.
PAGE 2
PIC16C745/765 2. Module: USTAT Register Work around The TOK_DNE bit (UIR Bit 3) is not set correctly for pending USB transactions in the USTAT register (see Figure 2). If additional transactions arrive prior to clearing the TOK_DNE bit, they will be lost. FIGURE 2: The interrupt driver Microchip firmware does not lose any transactions with current operating systems. UIR / USTAT REGISTER USTAT UIR QUEUE not empty TOK_DNE bit DS80114C-page 2 FIFO  2002 Microchip Technology Inc.
PAGE 3
PIC16C745/765 Clarifications/Corrections to the Data Sheet: In the Device Data Sheet, the following clarifications and corrections should be noted. 1. Module: Timer1 In Section 7.0, Timer1 module, there is an error in Figure 7-1. The label FINT should read FINT/4.
PAGE 4
PIC16C745/765 APPENDIX A: REVISION HISTORY Rev A Document (9/01) Original Errata document. Issue 1 (USTAT Register) was added (page 1). USB Transceiver Timing was added to page 1. Rev B Document (6/02) Under the Clarifications/Corrections to the Data Sheet, Issue 1 (Timer1) was added (page 2). Rev C Document (9/02) All reference to PIC16C745 in this Errata document is changed to PIC16C745/765. All reference to Rev. A in this Errata document is changed to Rev. A1.
PAGE 5
Note the following details of the code protection feature on PICmicro® MCUs. • • • • • • The PICmicro family meets the specifications contained in the Microchip Data Sheet. Microchip believes that its family of PICmicro microcontrollers is one of the most secure products of its kind on the market today, when used in the intended manner and under normal conditions. There are dishonest and possibly illegal methods used to breach the code protection feature.
PAGE 6
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