Motore di ricerca datesheet componenti elettronici |
|
74ABT899 Scheda tecnica(PDF) 2 Page - Fairchild Semiconductor |
|
74ABT899 Scheda tecnica(HTML) 2 Page - Fairchild Semiconductor |
2 / 16 page www.fairchildsemi.com 2 Pin Descriptions Functional Description The ABT899 has three principal modes of operation which are outlined below. These modes apply to both the A-to-B and B-to-A directions. • Bus A (B) communicates to Bus B (A), parity is gener- ated and passed on to the B (A) Bus as BPAR (APAR). If LEB (LEA) is HIGH and the Mode Select (SEL) is LOW, the parity generated from B[0:7] (A[0:7]) can be checked and monitored by ERRB (ERRA). • Bus A (B) communicates to Bus B (A) in a feed-through mode if SEL is HIGH. Parity is still generated and checked as ERRA and ERRB in the feed-through mode (can be used as an interrupt to signal a data/parity bit error to the CPU). • Independent Latch Enables (LEA and LEB) allow other permutations of generating/checking (see Function Table below). Function Table H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial Note 1: O/E = ODD/EVEN Pin Names Descriptions A0–A7 A Bus Data Inputs/Data Outputs B0–B7 B Bus Data Inputs/Data Outputs APAR, BPAR A and B Bus Parity Inputs/Outputs ODD/EVEN ODD/EVEN Parity Select, Active LOW for EVEN Parity GBA, GAB Output Enables for A or B Bus, Active LOW SEL Select Pin for Feed-Through or Generate Mode, LOW for Generate Mode LEA, LEB Latch Enables for A and B Latches, HIGH for Transparent Mode ERRA, ERRB Error Signals for Checking Generated Parity with Parity In, LOW if Error Occurs Inputs Operation GAB GBA SEL LEA LEB H H X X X Busses A and B are 3-STATE. H L L L H Generates parity from B[0:7] based on O/E (Note 1). Generated parity → APAR. Generated parity checked against BPAR and output as ERRB. HL L H H Generates parity from B[0:7] based on O/E. Generated parity → APAR. Gener- ated parity checked against BPAR and output as ERRB. Generated parity also fed back through the A latch for generate/check as ERRA. HL L X L Generates parity from B latch data based on O/E. Generated parity → APAR. Generated parity checked against latched BPAR and output as ERRB. H L H X H BPAR/B[0:7] → APAR/A0:7] Feed-through mode. Generated parity checked against BPAR and output as ERRB. H L H H H BPAR/B[0:7] → APAR/A[0:7] Feed-through mode. Generated parity checked against BPAR and output as ERRB. Generated parity also fed back through the A latch for generate/check as ERRA. LH L H L Generates parity for A[0:7] based on O/E. Generated parity → BPAR. Gener- ated parity checked against APAR and output as ERRA. LH L H H Generates parity from A[0:7] based on O/E. Generated parity → BPAR. Gener- ated parity checked against APAR and output as ERRA. Generated parity also fed back through the B latch for generate/check as ERRB. LH L L X Generates parity from A latch data based on O/E. Generated parity → BPAR. Generated parity checked against latched APAR and output as ERRA. L H H H L APAR/A[0:7] → BPAR/B[0:7] Feed-through mode. Generated parity checked against APAR and output as ERRA. L H H H H APAR/A[0:7] → BPAR/B[0:7] Feed-through mode. Generated parity checked against APAR and output as ERRA. Generated parity also fed back through the B latch for generate/check as ERRB. |
Codice articolo simile - 74ABT899 |
|
Descrizione simile - 74ABT899 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEETIT.COM |
Lei ha avuto il aiuto da alldatasheet? [ DONATE ] |
Di alldatasheet | Richest di pubblicita | contatti | Privacy Policy | scambio Link | Ricerca produttore All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |