Matrix-orbital VFD2041 Legacy Bedienungsanleitung PDF herunterladen (Seite 13)

Table 5: Serial Baud Rates

Baud Rate Slave Address J3 J2 J1 J0

1200 50H out out out out

52H out out out in

2400 54H out out in out

56H out out in in

9600 58H out in out out

5AH out in out in

19200 5CH out in in out

5EH out in in in

1200 60H in out out out

62H in out out in

2400 64H in out in out

66H in out in in

9600 68H in in out out

6AH in in out in

19200 6CH in in in out

6EH in in in in

2.3 I

C Communications

C communications runs at 100 Kbps and supports up to 16 units on a single communications line. The

C data line operates on 5 volt CMOS levels.

2.3.1 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 bytes transition. They are only capable of

failing to acknowledge the bytes following the byte, which was not received. To fully understand the reasons

for this one needs to understand something about how a Matrix Orbital module processes data. Basically the

reason why a Matrix Orbital module might fail to receive a byte correctly is that it was unable to process the

byte previous before the failed byte was transmitted. Because the module cannot possibly know that it would

be unable to store the byte before the next byte was received it cannot know to not ACK. The reason for this

situation in deference to situations one might be familiar with (i.e., memory chips, etc) is that the Matrix

Orbital module employs a micro-processor to perform these data storage functions. A memory chip takes

care of these things entirely with in hardware subsystems that operate at the same speed as the transmission

themselves.

The display uses a standard Phillips 7bit address as deﬁned by Phillips. However, Matrix Orbital speciﬁes

C address in 8bits. The 8th bit, least signiﬁcant bit (LSB or Low Order Bit) of the 8bit address is read

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Matrix-orbital VFD2041 Legacy Bedienungsanleitung Seite 13