GS2101M IP2WiFi Adapter Command Reference Guide
1VV0301499
Rev. 2.0
40
2019-08-05
The HI Format is used for the message exchange. Refer to
3.2.2.4 Annexure - HI Frame Response (From GS
.
Based on MCU capabilities (such as multi threaded application, single threaded
application, interrupt supported application, and so on), SPI command response method
supports the following methodologies to transfer data between MCU and GS node.
•
Interrupt methodology
•
Polling methodology
3.2.2.2.1 Interrupt Methodology
This methodology is used if the MCU is running at higher clock speed and run into false
detection of GPIO37 status. MCU should configure interrupt on rising edge of the pin
connected to GPIO37 in GS.
The following section provides steps involved while transferring data from MCU to GS
node using Interrupt based methodology.
Transferring Data
from MCU to
GS
Node
1. MCU sends first four bytes of WRITE_REQUEST to GS node. It waits for minimum
of 3.2 microseconds and rearms the interrupt handler which discards all the previous
interrupts.
2. GS node receives four bytes of WRITE_REQUEST in SPI FIFO. It triggers an
interrupt to pull the GPIO37 low (This step is performed although GPIO37 is low).
NOTE: 1.)
The MCU waits for 3.2 microseconds as it is the minimum time
required for the hardware and software latency. The following steps describe how
an interrupt is processed:
a.) SPI FIFO triggers an interrupt as soon as it receives the first four bytes of data
from MCU. This ISR will pull down GPIO37 only if the data is
READ_REQUEST/WRITE_REQUEST. MCU needs to check or wait for the
GPIO37 to go low.
b.) Interrupt is sent to the interrupt controller
c.) Interrupt controller intimates the APP CPU about the interrupt
d.) OS scheduler checks for any pending interrupt and runs the corresponding
ISR (Interrupt Service Routine) as ISRs have the highest priority
