PIC16C745/P Microchip Technology, PIC16C745/P Datasheet - Page 70

• Manufacturer Part Number: PIC16C745/P
• Description: 8-Bit CMOS Microcontrollers with USB
• Manufacturer: Microchip Technology

PIC16C745/765
REGISTER 10-12: BUFFER DESCRIPTOR BYTE COUNT (BDndBC: 1A1h, 1A5h, 1A9h, 1ADh, 1B1h,
REGISTER 10-13: BUFFER DESCRIPTOR ADDRESS LOW (BDndAL: 1A2h, 1A6h, 1AAh, 1AEh,
10.6.1
Endpoint buffers are located in the Dual Port RAM
area. The starting location of an endpoint buffer is
determined by the Buffer Descriptor.
10.7
An on-chip integrated transceiver is included to drive
the D+/D- physical layer of the USB.
10.7.1
A 3.3V regulator provides the D+/D- drives with power.
A +20% 10nF capacitor is required on V
tor stability.
TABLE 10-1:
DS41124A-page 70
V
D-
D+
Legend:
USB
bit7
bit 7-4: Reserved: Read as ’X’.
bit 3-0: BC<3:0>: The Byte Count bits represent the number of bytes that will be transmitted for an IN TOKEN or
bit7
bit 7-0: BA<7:0>: Buffer Address. The base address of the buffer controlled by this endpoint. The upper order bit
Note 1: This register should always contain a value between B8h-DFh.
R/W-X
BA7
U-X
—
ENDPOINT BUFFERS
TRANSCEIVER
REGULATOR
received during an OUT TOKEN. Valid byte counts are 0 - 8. The SIE will change this field upon the com-
pletion of an OUT or SETUP token with the actual byte count of the data received.
address (BA8) of the 9-bit address is assumed to be 1h. This value must point to a location within the dual
port memory space (1B8h - 1DFh). The upper order bits of the address are assumed to point to Bank 3.
OD = open drain, ST = Schmitt Trigger
Name
R/W-X
BA6
U-X
—
USB PORT FUNCTIONS
1B5h))
1B2h, 1B6h)
R/W-X
BA5
U-X
—
Function
V
R/W-X
D+
USB
D-
BA4
U-X
—
USB
Advanced Information
for regula-
R/W-X
R/W-X
Input
Type
USB
USB
BC3
BA3
—
Output
Power
R/W-X
R/W-X
Type
USB
USB
BC2
BA2
10.7.1.1
The V
current is sufficient for a pull-up only.
10.8
Microchip Technology provides a comprehensive set
of Chapter 9 Standard requests functions to aid devel-
opers in implementing their designs. See Microchip
Technology’s website for the latest version of the soft-
ware libraries.
3.3V for pull up resistor
USB Differential Bus
USB Differential Bus
R/W-X
R/W-X
BC1
BA1
USB
USB Software Libraries
provides a 3.3V nominal output. This drive
V
USB
R/W-X
R/W-X
BC0
BA0
Output
bit0
bit0
Description
1999 Microchip Technology Inc.
R = Readable bit
W = Writable bit
U = Unimplemented bit,
-n = Value at POR reset
X = Don’t care
R = Readable bit
W = Writable bit
U = Unimplemented bit,
-n = Value at POR reset
X = Don’t care
read as ‘0’
read as ‘0’