Forgive the poor title, I really don't know how to best summarize this. I'm a bit of an amateur in regards to these two questions, and nothing I've been able to research seems to hold the answers. So I'll just post them here, if any of you know how to figure this out (I hope the memory forum was the best place to post this):
1. Given an RS-232 serial interface with the following parameters: 8 bits of data, EVEN parity, one stop bit and 38,400 bits per second (38,400-E-1). There is no idle time between the end of the stop bit of a data element and the start bit of the next one. What is the total amount of time needed to send 128 of these 8-bit data words over this serial link?
Such is how much of an amateur I am that this is all I can think of:
128 * 8 = 1024 bits to send
1024 bits / 38400 (bits/s) = 0.0267 seconds
As you can see, I can't figure out how 'even' parity, or one stop bit effects the time involved, specifically. I'm fairly stumped.
2. A new satellite data processing center has just been completed and ready for the initial testing using live data being sent down from an orbiting satellite. As the very first messages are on the screen and you notice many of the data values are wildly out of range.
For example, on the terminal screen is something defined as “delta time” seems to be out of the expected range [0.01 to 10,000.00 seconds], but the value displayed (as a double) is [-4.12318024e-028]. After further investigation into the raw byte-based data stream, you find the original data being sent down from the satellite for this double word as [0xC0 0x83 0xA1 0xCA 0x66 0x55 0x40 0xBA]. On this new machine used to display the data, this 64-bit data item does convert to the value displayed, but on one of the older terminals, the value is within range.
a. What caused this problem?
b. If this is the real problem, what should the actual value be?
Again, my pathetic attempt is the following:
0xC0 = 12
0x83 = 131
0xA1 = 11
0xCA = 22
0x66 = 102
0x55 = 85
0x40 = 64
0xBA = 21
Total = 448
a...Endians? b...448?
Clearly I don't really know what I'm doing. I just have a hunch that it has to do with Endians, but I can't figure out what it could be, if that's even true.
Does anyone have any idea for either of these?
1. Given an RS-232 serial interface with the following parameters: 8 bits of data, EVEN parity, one stop bit and 38,400 bits per second (38,400-E-1). There is no idle time between the end of the stop bit of a data element and the start bit of the next one. What is the total amount of time needed to send 128 of these 8-bit data words over this serial link?
Such is how much of an amateur I am that this is all I can think of:
128 * 8 = 1024 bits to send
1024 bits / 38400 (bits/s) = 0.0267 seconds
As you can see, I can't figure out how 'even' parity, or one stop bit effects the time involved, specifically. I'm fairly stumped.
2. A new satellite data processing center has just been completed and ready for the initial testing using live data being sent down from an orbiting satellite. As the very first messages are on the screen and you notice many of the data values are wildly out of range.
For example, on the terminal screen is something defined as “delta time” seems to be out of the expected range [0.01 to 10,000.00 seconds], but the value displayed (as a double) is [-4.12318024e-028]. After further investigation into the raw byte-based data stream, you find the original data being sent down from the satellite for this double word as [0xC0 0x83 0xA1 0xCA 0x66 0x55 0x40 0xBA]. On this new machine used to display the data, this 64-bit data item does convert to the value displayed, but on one of the older terminals, the value is within range.
a. What caused this problem?
b. If this is the real problem, what should the actual value be?
Again, my pathetic attempt is the following:
0xC0 = 12
0x83 = 131
0xA1 = 11
0xCA = 22
0x66 = 102
0x55 = 85
0x40 = 64
0xBA = 21
Total = 448
a...Endians? b...448?
Clearly I don't really know what I'm doing. I just have a hunch that it has to do with Endians, but I can't figure out what it could be, if that's even true.
Does anyone have any idea for either of these?
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