 |
Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
|
Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
MC68HC000 Datasheet(PDF) 41 Page - Freescale Semiconductor, Inc |
|
||||||||||||||||||||||||||||||
MC68HC000 Datasheet(HTML) 41 Page - Freescale Semiconductor, Inc |
|
|
41 / 189 page  MOTOROLA M68000 8-/16-/32-BIT MICROPROCESSORS USER'S MANUAL 4- 3 A bus cycle consists of eight states. The various signals are asserted during specific states of a read cycle, as follows: STATE 0 The read cycle starts in state 0 (S0). The processor places valid function codes on FC0–FC2 and drives R/W high to identify a read cycle. STATE 1 Entering state 1 (S1), the processor drives a valid address on the address bus. STATE 2 On the rising edge of state 2 (S2), the processor asserts AS and LDS, or DS. STATE 3 During state 3 (S3), no bus signals are altered. STATE 4 During state 4 (S4), the processor waits for a cycle termination signal (DTACK or BERR) or VPA, an M6800 peripheral signal. When VPA is asserted during S4, the cycle becomes a peripheral cycle (refer to Appendix B M6800 Peripheral Interface). If neither termination signal is asserted before the falling edge at the end of S4, the processor inserts wait states (full clock cycles) until either DTACK or BERR is asserted. STATE 5 During state 5 (S5), no bus signals are altered. STATE 6 During state 6 (S6), data from the device is driven onto the data bus. STATE 7 On the falling edge of the clock entering state 7 (S7), the processor latches data from the addressed device and negates AS and LDS , or DS. At the rising edge of S7, the processor places the address bus in the high- impedance state. The device negates DTACK or BERR at this time. NOTE During an active bus cycle, VPA and BERR are sampled on every falling edge of the clock beginning with S4, and data is latched on the falling edge of S6 during a read cycle. The bus cycle terminates in S7, except when BERR is asserted in the absence of DTACK. In that case, the bus cycle terminates one clock cycle later in S9. 4.1.2 Write Cycle During a write cycle, the processor sends bytes of data to the memory or peripheral device. Figures 4-3 and 4-4 illustrate the write-cycle operation The 8-bit operation performs two write cycles for a word write operation, issuing the data strobe signal during each cycle. The address bus includes the A0 bit to select the desired byte. Freescale Semiconductor, Inc. For More Information On This Product, Go to: www.freescale.com |
Número de pieza similar - MC68HC000 |
|
Descripción similar - MC68HC000 |
|
|
Enlace URL |
| Política de Privacidad |
| ALLDATASHEET.ES |
| ¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Intercambio de Enlaces | Lista de Fabricantes 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 |
Spanish ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
