UPSD3254 STMICROELECTRONICS [STMicroelectronics], UPSD3254 Datasheet - Page 95

• Manufacturer Part Number: UPSD3254
• Description: Flash Programmable System Devices with 8032 Microcontroller Core
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

The USCL 8-bit Prescaler Register for USB is at
E1h. The USCL should be loaded with a value that
results in a clock rate of 6MHz for the USB using
the following formula:
Where f
Table 80. USB SFR Memory Map
Addr
SFR
EC UCON2
ED
EA UCON0
EB UCON1
EE
EF
E1
E6
E7
E8
E9
USB clock input =
(f
UISTA
UADR
OSC
Name
USCL
UDR0
UDT1
UDT0
USTA
UIEN SUSPNDIE RSTE
Reg
OSC
/ 2) / (Prescaler register value +1)
is the MCU clock input frequency.
SUSPND
UDR0.7
UDT1.7
UDT0.7
USBEN
TSEQ0
TSEQ1
RSEQ
—
7
EP12SEL
STALL0
UDR0.6 UDR0.5 UDR0.4 UDR0.3 UDR0.2 UDR0.1
UDT1.6
UDT0.6
UADD6
SETUP
—
—
6
RSTFIE TXD0IE RXD0IE TXD1IE
UDT1.5
UDT0.5
UADD5
RSTF
TX0E
—
—
IN
5
UPSD3254A, UPSD3254BV, UPSD3253B, UPSD3253BV
Bit Register Name
FRESUM TP1SIZ3 TP1SIZ2 TP1SIZ1 TP1SIZ0
UDT1.4
UDT0.4
UADD4
TXD0F
SOUT
RX0E
OUT
4
RP0SIZ3 RP0SIZ2 RP0SIZ1 RP0SIZ0
TP0SIZ3 TP0SIZ2 TP0SIZ1 TP0SIZ0
UDT1.3
UDT0.3
UADD3
RXD0F
EP2E
3
Note: USB works ONLY with the MCU Clock fre-
quencies of 12, 24, or 36MHz. The Prescaler val-
ues for these frequencies are 0, 1, and 2.
UDT1.2
UDT0.2
UADD2
RXD1F
EP1E
2
STALL2
UDT1.1
UDT0.1
UADD1
EOPIE RESUMIE
EOPF
1
RESUMF
STALL1
UDR0.0
UDT1.0
UDT0.0
UADD0
0
Reset
Value
00
00
00
00
00
00
00
00
00
00
00
Prescaler for
USB Control
USB Endpt1
USB Endpt0
USB Endpt0
Xmit Control
USB Endpt1
Xmit Control
USB Endpt0
USB Endpt0
Comments
Data Recv
USB logic
Data Xmit
Data Xmit
Interrupt
Interrupt
Register
Address
Register
Enable
Status
Status
USB
USB
USB
8-bit
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