ST72651AR6 STMicroelectronics, ST72651AR6 Datasheet - Page 70

• Manufacturer Part Number: ST72651AR6
• Description: LOW-POWER, FULL-SPEED USB 8-BIT MCU WITH 32K FLASH, 5K RAM, FLASH CARD I/F, TIMER, PWM, ADC, I2C, SPI
• Manufacturer: STMicroelectronics

Specifications of ST72651AR6

• Dual Supply Management: analog voltage detector on the USB power line to enable smart power switching from USB power to battery (on E suffix devices).
• Programmable Internal Voltage Regulator For Memory Cards (2.8v To 3.5v) Supplying: Flash Card I/O lines (voltage shifting)
• 5 Usb Endpoints: 1 control endpoint
• Dtc (data Transfer Coprocessor): Universal Serial/Parallel communications interface, with software plug-ins for current and future protocol standards

ST72651AR6
USB INTERFACE (Cont’d)
Bits 2:0 = ERR[2:0] Error type.
These bits identify the type of error which oc-
curred:
Note: These bits are set by hardware when an er-
ror interrupt occurs and are reset automatically
when the error bit (ISTR bit 4) is cleared by soft-
ware.
ENDPOINT 0 REGISTER (EP0R)
Read/Write
Reset value: 0000 0000 (00h)
This register is used for controlling Endpoint 0. Bits
6:4 and bits 2:0 are also reset by a USB reset, ei-
ther received from the USB or forced through the
FRES bit in CTLR.
Bit 7 = CTR0 Correct Transfer.
This bit is set by hardware when a correct transfer
operation is performed on Endpoint 0. This bit
must be cleared after the corresponding interrupt
has been serviced.
0: No CTR on Endpoint 0
1: Correct transfer on Endpoint 0
Bit 6 = DTOG_TX Data Toggle, for transmission
transfers.
It contains the required value of the toggle bit
(0=DATA0, 1=DATA1) for the next transmitted
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1
ERR2 ERR1 ERR0
CTR0
0
0
0
0
1
1
1
7
DTOG
_TX
0
0
1
1
0
0
1
STAT_
TX1
0
1
0
1
0
1
1
STAT_
No error
Bitstuffing error
CRC error
EOP error (unexpected end of
packet or SE0 not followed by
J-state)
PID error (PID encoding error,
unexpected or unknown PID)
Memory over / underrun (mem-
ory controller has not an-
swered in time to a memory
data request)
Other error (wrong packet, tim-
eout error)
TX0
0
Meaning
DTOG
_RX
STAT_
RX1
Doc ID 7215 Rev 4
STAT_
RX0
0
data packet. This bit is set by hardware on recep-
tion of a SETUP PID. DTOG_TX toggles only
when the transmitter has received the ACK signal
from the USB host. DTOG_TX and also
DTOG_RX are normally updated by hardware, on
receipt of a relevant PID. They can be also written
by the user, both for testing purposes and to force
a specific (DATA0 or DATA1) token.
Bits 5:4 = STAT_TX [1:0] Status bits, for transmis-
sion transfers.
These bits contain the information about the end-
point status, as listed below:
Table 20. Transmission Status Encoding
These bits are written by software. Hardware sets
the STAT_TX and STAT_RX bits to NAK when a
correct transfer has occurred (CTR=1) addressed
to this endpoint; this allows software to prepare the
next set of data to be transmitted.
Bit 3 = Reserved, forced by hardware to 0.
Bit 2 = DTOG_RX Data Toggle, for reception
transfers.
It contains the expected value of the toggle bit
(0=DATA0, 1=DATA1) for the next data packet.
This bit is cleared by hardware in the first stage
(Setup Stage) of a control transfer (SETUP trans-
actions start always with DATA0 PID). The receiv-
er toggles DTOG_RX only if it receives a correct
data packet and the packet’s data PID matches
the receiver sequence bit.
STAT_TX1 STAT_TX0
0
0
1
1
0
1
0
1
DISABLED: no function can be
executed on this endpoint and
messages related to this end-
point are ignored.
STALL: the endpoint is stalled
and all transmission requests
result in a STALL handshake.
NAK: the endpoint is NAKed
and all transmission requests
result in a NAK handshake.
VALID: this endpoint is enabled
(if an address match occurs, the
USB interface handles the
transaction).
Meaning