Matrix Orbital VK162-12 Legacy - Manual (Page 14)

Table 4: Connector Pinout
Pin 4 Ground
Pin 3 Rx
Pin 2 Tx
Pin 1 Vdc
2.1.8 TTL Communications
The display can be talked to at TTL (logic 0V to +5V) levels. Two modifications must be made.
Figure 13: RS-232 Selects
Jumpers 2 and 3 must be closed and 1 and 4 open.
2.1.9 I 2 C Communications
I 2 C communications runs at 100Kbps and supports up to 127 units on a single communications line. The
I 2 C data line operates on 5 volt CMOS levels.
2.1.10 ACK
The idea of ACK is to indicate when the data has been received correctly. ACK does not indicate data
incorrectly received. ACK simply fails to indicate when data is correctly received. Clearly, this is of limited
usefulness and even less so with Matrix Orbital modules. Matrix orbital modules are not capable of failing
to acknowledge an incorrectly received byte in response to that byte’s transition. They are only capable of
failing to acknowledge the bytes following the byte, which was not received. To fully understand the reasons
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