ht82a523r Holtek Semiconductor Inc., ht82a523r Datasheet - Page 21

• Manufacturer Part Number: ht82a523r
• Description: Ht82a523r -- Usb 2.0 Full Speed 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

DMA Function
DMA function is enabled when DMA bit of the USB MISC
register is set to 1. If DMA function is enabled, either the
SBDR of the serial interface 1 (which is pin-shared with
port E) or the SBDR of the serial interface 2 (which is
pin-shared with port C) will be written to the FIFO3 directly.
If SBEN bit and DMA bit are set, the SPI interface which
is select with DMASEL bit will send out the SCKA clock
during master mode. The frequency of the SCKA is con-
trolled by CKS & M1 & M0 also. The SCKA clock output
will be stopped automatically when FIFO3 is full and will
restart automatically when FIFO3 is not full.
The SCKA clock will stay at low level if CPOL is 1 and
stay at high level if CPOL is 0 when it is stopped.
Suspend Wake-Up or Remote Wake-Up
If there is no signal on the signal bus for over 3ms, the
HT82A523R will go into suspend mode. The Suspend
line (bit 0 of the USC) will be set to 1 and a USB interrupt
is triggered to indicate that the HT82A523R should jump
to suspend state to meet the 500 A USB suspend cur-
rent spec.
In order to meet the 500 A suspend current, the firm-
ware should disable the USB clock by clearing the
USBCKEN (bit3 of the UCC) to 0 . The suspend cur-
rent is about 400 A.
The user can also further decrease the suspend current by
setting the SUSP2 (bit4 of the UCC). But if the SUSP2 is
set, user should make sure not to enable the LVR OPT op-
tion, otherwise, the HT82A523R will be reset. If user set
the SUSP2 (bit4 of the UCC) In the USB mode, user
must set Rctrl (bit7 of the UCC) before set SUSP2 (bit4
of the UCC), otherwise, USB will disconnected.
When the resume signal is sent out by the host, the
HT82A523R will wake-up the by USB interrupt and the
Resume line (bit 3 of the USC) is set. In order to make
Rev. 1.30
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the HT82A523R work properly, the firmware must set
the USBCKEN (bit 3 of the UCC) to 1 and clear the
SUSP2 (bit4 of the UCC). If user set the Rctrl (bit7 of the
UCC) and SUSP2 (bit4 of the UCC) In the USB sus-
pend, when it will wake-up user must clr Rctrl (bit7 of the
UCC) before clr SUSP2 (bit4 of the UCC). Since the Re-
sume signal will be cleared before the Idle signal is sent
out by the host and the Suspend line (bit 0 of the USC) is
going to 0 . So when the MCU is detecting the Suspend
line (bit0 of USC), the Resume line should be remem-
bered and taken into consideration.
After finishing the resume signal, the suspend line will
go inactive and a USB interrupt is triggered. The follow-
ing is the timing diagram:
The device with remote wake-up function can wake-up
the USB Host by sending a wake-up pulse through
RMWK (bit 1 of the USC). Once the USB Host receive
the wake-up signal from the HT82A523R, it will send a
Resume signal to the device. The timing is as follow:
USB Interface
The HT82A523R has 4 Endpoints (EP0~EP3).
EP0~EP2 are support Interrupt transfer, EP3 is support
Bulk transfer.
There are 12 registers, including USC (20H), USR
(21H), UCC (22H), AWR (address+remote wake-up
23H), STALL (24H), SIES (25H), MISC (26H), SETIO
(27H), FIFO0 (28H), FIFO1 (29H), FIFO2 (2AH) and
FIFO3 (2BH) used for the USB function.
HT82A523R
May 13, 2008