73S1215F Data Sheet
DS_1215F_003
1.7.14.1 USB Interface Implementation
The 73S1215F Application Programming Interface includes some dedicated software commands to
configure the USB interface, to get a status of each USB Endpoint, to stall / unstall portions of the USB,
and to send / receive data to / from each endpoint.
USB API entirely manages the USB circuitry, the USB registers and the FIFOs. Use of those commands
facilitates USB implementation, without dealing with low-level programming.
Miscellaneous Control Register 1 (MISCtl1): 0xFFF2 Å 0x10
Table 78: The MISCtl1 Register
MSB
LSB
ANAPEN USBPEN USBCON
–
–
FRPEN FLSH66
–
Bit
Symbol
Function
MISCtl1.7
MISCtl1.6
MISCtl1.5
MISCtl1.4
MISCtl1.3
MISCtl1.2
MISCtl1.1
–
–
FRPEN
FLSH66
–
Flash Read Pulse enable.
Flash Read Pulse.
ANAPEN Analog power enable.
USBPEN 0 = Enable the USB differential transceiver.
1 = Connect pull-up resistor from VDD to D+. If connected, the USB
USBCON host will recognize the attachment of a USB device and begin
enumeration.
MISCtl1.0
Note: When using the USB on the 73S1215F, external 24Ω series resistors must be added to the D+ and
D- signals to provide the proper impedance matching on these pins.
The USB peripheral block is not able to support read or write operations to the USB SFR registers when
the MPU clock is running at MPU clock rates of 12MHz or greater. In order to properly communicate with
the USB SFR registers when running at these speeds, wait states must be inserted when addressing the
USB SFRs. The CKCON register allows wait states to be inserted when accessing these registers. The
proper settings for the number of wait states are shown in Error! Reference source not found..
When changing the MPU clock rate or the number of wait states, the USB connection
must be inactive. If the USB is active, then it must be inactivated before changing the
MPU clock or number of wait states. It can then be reconnected and re-enumerated.
Changing these parameters while the USB interface is active may cause communication errors on
the USB interface.
74
Rev. 1.4
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
