SENA HD1200 - Manual (Page 31)

Starter Kit and User Manual for the HelloDevice 1200
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certain area of Dual-Port RAM. Then, your device may perform certain device-specific tasks by using the data
read from the memory.
e.g. an interrupt service routine of your device may read specified memory area first and then it may display the
LCD screen from this data or may drive actuators from the data.
Note:
the HelloDevice does not have any interrupt reentrancy-protection mechanism. Thus, the processing time of the
interrupt service routine should be less than 5 ms, since the minimal time required to generate interrupt from the
HelloDevice is 5 ms. This is the case that next interrupt may be generated before the previous interrupt service
routine is finished. There will be no problem, if your device services interrupt from the HelloDevice in less than
5 ms. If a host application sends data at the interval larger than 5 ms, there may not be any problem.
B. Your device requests the HelloDevice to read data from Dual-Port RAM area
This interrupt is used when your device want to inform the HelloDevice of the fact that it has updated the certain
area of Dual-Port RAM. Then, the HelloDevice will read this data first and then it will send this data to the host
PC connected to the HelloDevice, by TCP/IP protocol.
e.g. your device may be composed of sensors for temperature, pressure or some other sensing units. Whenever
the sensor output is updated, your device may notify the fact to the HelloDevice. Eventually, the data will be sent
to application of host PC.
Note:
Interrupt generation interval of your device should be larger than 5 ms, since the minimal time required to
process interrupt from your device is 5 ms.
Fig 6.3 shows the flow chart that the user device generates interrupting into the HelloDevice for sending data to
PC. Fig 6.4 shows the flow chart that HelloDevice generates interrupting of dual port ram Read to the user
device so that user device can read data from the HelloDevice. The terminologies, IN/OUT used in the figure are
described in terms of interrupt direction. In the HelloDevice side, it will be In, if interrupt is generated into the
HelloDevice from your device or vice versa. The symbols of OUTAddr, OUTLen, INAddr, INLen is described in
Table 6.1, Interrupt control register.