GS2101M IP2WiFi Adapter Command Reference Guide
1VV0301499
Rev. 2.0
39
2019-08-05
One dedicated GPIO signal (
GS_SPI _HOST_WAKEUP)
is available for data ready
indications from Slave GS node to Master Host controller. This
GS_SPI
_HOST_WAKEUP
signal is asserted high during valid data transmission period, so that the
host (master SPI) starts pulling out data by giving SPI clock and
GS_SPI
_HOST_WAKEUP
signal is de-asserted once transmission is completed. It is only pulled
high for the actual data and not for the control characters. Master host controller must
provide clock as long as
GS_SPI_HOST_WAKEUP
signal is active
.
Special character (
GS_SPI _IDLE
) will be transmitted during idle period (if there is no
more data to transmit) and must be dropped at the receiving Host.
SPI receive data handling procedure
:
Since byte stuffing is used, each Control Escape octet must be removed and the next
immediate octet is exclusive-or’d (XOR) with hexadecimal
0x20
. If received buffer has
reached the upper water mark, then
XOFF
character will be sent out informing the host to
stop transmitting actual data. After receiving
XOFF
character host must stop transmitting
actual data and can send IDLE bytes, until the
XON
is received. Once the host receives
XON
, then it may resume the valid data transmissions.
Special control byte
IDLE
will be dropped at receiver.
3.2.2.2 SPI Command Response (SPI-DMA)
This method is used to achieve high throughput over SPI by using:
–
Higher clock rate up to 10Mhz (when running @120Mhz)
–
DMA access for the data transfer
This interface uses command response handling between GS node (always slave) and any
MCU (always master which controls the clock) through SPI interface. MCU issues
commands for read/write and waits for the response.
If the response indicates:
–
Success: the action is taken
–
Failure: the action is deferred and retried after some time or dropped.
Operation sequence:
Command > Response > Data phase (if response success) >
Command > Response > Data phase (response success).
0xFB
0xFB 0xDB
Control ESCAPE
0xF5
0xFB 0xD5
IDLE character
0xFF
0xFB 0xDF
Inactive link detection
0xF3
0xFB 0xD3
SPI link ready indication
Table 19 SPI Transmit Data Handling Link Pattern
Pattern
Encoded as
Description
