Additional Information on Serial Port Lines

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This topic contains information related to programming of the EM1202EV. It assumes that you are familiar with Tibbo BASIC/C and the concept of "platforms". Everything you need to know regarding this can be found in "TIDE and Tibbo BASIC Manual".

You can create Tibbo BASIC/C applications for the EM1202EV using two different platforms -- the "DS1202" platform and "EM1202" platform. The DS1202 platform can be used because the EM1202EV is, essentially, a DS1202 device without the plastic housing. The EM1202 platform can be used because the board is based on the EM1202 module.

Generally speaking, the EM1202 platform offers "more". It addresses every hardware faculty of the EM1202. The DS1202 platform is much more limited and only includes features that can be used when the EM1202 module is mounted on the EM1202EV board (inside the DS1202 device).

The biggest difference between the two platforms is in how the I/O lines are wired. The EM1202 platform defines 32 I/O lines. Half of these are not used on the EM1202EV, and the remaining lines are interconnected. Each line of the serial port (save for the "spare" line discussed previously) is connected to two GPIO lines of the EM1202. This was done to ensure more flexible mapping (see Multi-Channel Serial Port). Care should be taken to avoid enabling both outputs of the same serial port line simultaneously! This can permanently damage the EM1202. We suggest that you use GPIO8/P1.0/RX0 - GPIO14/P1.6/RX3 for actual input/output and use GPIO16/P2.0/INT0 - GPIO19/P2.3/INT3 as interrupt inputs only.

The DS1202 platform "looks" at the same hardware differently and defines fewer I/O lines. Each of the physical line pair is represented by a single GPIO line. GPIO lines of the EM1202 that are unused are not defined at all.

 

GPIO lines of the EM1202 platform -- two lines are connected to each serial port line, except in the case of the "spare" input

GPIO lines of the DS1202 platform

DB9M pin and its conventional function ("-RS")

TTL connector pin ("-TS", "-TM")

GPIO8/P1.0/RX0

GPIO16/P2.0/INT0

PL_IO_NUM_0_RX0_INT0

#2 (RX input)

#6

GPIO9/P1.1/TX0

GPIO20/P2.4/INT4

PL_IO_NUM_1_TX0_INT4

#3 (TX output)

#5

GPIO10/P1.2/RX1

GPIO17/P2.1/INT1

PL_IO_NUM_2_RX1_INT1

#8 (CTS input)

#4

GPIO11/P1.3/TX1

GPIO21/P2.5/INT5

PL_IO_NUM_3_TX1_INT5

#7 (RTS output)

#3

GPIO12/P1.4/RX2

GPIO18/P2.2/INT2

PL_IO_NUM_4_RX2_INT2

#6 (DSR input)

#7

GPIO13/P1.5/TX2

GPIO22/P2.6/INT6

PL_IO_NUM_5_TX2_INT6

#4 (DTR output)

#8

GPIO14/P1.6/RX3

GPIO19/P2.3/INT3

PL_IO_NUM_6_RX3_INT3

#9 (RI input)

#2

---

GPIO23/P2.7/INT7*

PL_IO_NUM_7_INT7

#1 (CD input)*

#1*

* Spare input (see above).