Timeline for Chip select for the ROM
Current License: CC BY-SA 4.0
16 events
| when toggle format | what | by | license | comment | |
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| Aug 21, 2022 at 20:05 | answer | added | Rajeev | timeline score: 0 | |
| Sep 27, 2020 at 14:11 | history | edited | Anshul Gupta | CC BY-SA 4.0 |
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| Sep 27, 2020 at 13:11 | history | edited | Anshul Gupta | CC BY-SA 4.0 |
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| Sep 27, 2020 at 13:04 | vote | accept | Anshul Gupta | ||
| Sep 27, 2020 at 13:01 | comment | added | user16324 | Making the CS = 0 for the correct addresses is only half the problem. You must also ensure it is 1 outside the correct address range. Review the choices with that in mind. | |
| Sep 27, 2020 at 12:42 | comment | added | Chris Stratton | Write a truth table for A15-A12 and see which satisfies it. There is a nasty practical issue of the ROM not being aligned, but that's not an issue for /CS generation. | |
| Sep 27, 2020 at 12:42 | answer | added | AJN | timeline score: 2 | |
| Sep 27, 2020 at 12:41 | comment | added | Anshul Gupta | Correct option is A. | |
| Sep 27, 2020 at 12:35 | comment | added | AJN |
I think only the higher order nibble is need to be analysed. The nibble A15A14A13A12 should be low only when 1) 0001; i.e. A15' . A14' . A13' . A12 OR, 2) 0010; i.e. A15' . A14' . A13 . A12'. The combination for low is then A15' . A14' . (A13' . A12 + A13' . A12) . Negate this to get the conditions for high. Does it match option (B)?
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| Sep 27, 2020 at 12:27 | comment | added | Anshul Gupta | I am not demanding the correct answer. In fact I know I know what the correct answer is. I want to know why option B is not correct. Since it also makes the CS signal 0. | |
| Sep 27, 2020 at 12:25 | history | edited | Anshul Gupta | CC BY-SA 4.0 |
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| Sep 27, 2020 at 12:23 | comment | added | Justme | Demanding the correct answer without knowing why it is the correct answer will not help you learn anything. | |
| Sep 27, 2020 at 12:23 | history | edited | Anshul Gupta | CC BY-SA 4.0 |
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| Sep 27, 2020 at 12:18 | comment | added | Anshul Gupta | Options A, B, C, D are equations for the CS signal. Which one of the following logic expression will generate correct CS signal for the ROM. | |
| Sep 27, 2020 at 12:16 | comment | added | Justme | Well which addresses do the equations decode to, and which one matches the required address? | |
| Sep 27, 2020 at 12:11 | history | asked | Anshul Gupta | CC BY-SA 4.0 |