 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
Z80 Datasheet(PDF) 40 Page - Zilog, Inc. |
|
|
|||||||||||||||||||||||||||||
Z80 Datasheet(HTML) 40 Page - Zilog, Inc. |
|
|
40 / 330 page  <%27 2GTKRJGTCNU 7UGT /CPWCN UM008101-0601 Counter/Timer Channels Loading The Time Constant Register A Time Constant Data Word is written to the Time Constant register by the CPU. This event occurs on the I/O Write Cycle following that of the channel control word. The Time Constant Data Word may be any integer value in the range 1-256 (Table 6). If all eight bits in this word are zero, it is interpreted as 256. If a Time Constant Date Word is loaded to a channel already in operation, the down-counter continues decrementing to zero before the new time constant is loaded. Loading The Interrupt Vector Register The Z80 CTC operates with the Z80 CPU programmed for mode 2 interrupt response. When a CTC interrupt request is acknowledged, a 16-bit pointer is formed to obtain a corresponding interrupt service routine starting address (Figure 8). The upper eight bits of this pointer are provided by the CPU’s I register; the lower eight bits are provided by the CTC in the form of an interrupt vector unique to the requesting channel (Figure 8). For further details, see “CTC Interrupt Servicing” on page 27. The five high-order bits of the interrupt vector are written to the CTC in advance as part of the initial programming sequence. The CPU writes to the I/O port address corresponding to the CTC Channel 0. A 0 in bit 0 signals the CTC to load the incoming word into the interrupt vector register. When the interrupt vector is placed on the Z80 data bus, the interrupt control logic of the CTC automatically supplies a binary code in bits 1 and 2 identifying which of the four CTC channels is to be serviced. Table6.TimeConstant Register 765 4321 0 TC7 TC6 TC5 TC4 TC3 TC2 TC1 TC0 R/W R/W R/W R/W R/W R/W R/W R/W |
|
Link URL |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link to Datasheet | Link Exchange | Manufacturer List 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
