Campbell Scientific CR10 CR10 Measurement and Control - Page 77

SECTION 6. g.PIN SERIAL INPUT/OUTPUT an SD is enabled by an address synchronously clocked from the CR10 (Section 6.6). Up to 16 SDs may be addressed by the CH10. Unlike an enabled peripheral, the CR10 establishes communication with an addressed peripheral before data are transferred. During data transfer an addressed peripheral uses pin 7 as a handshake line with the CR10. RING RA|SE CLKIHS Synchronously addressed peripherals include the CR1OKD Keyboard Display, SM716 and SMl92 Storage Modules, SDC99 Synchronous Device Interface (SDC99), and RF95 RF Modem when configured as a synchronous device. The SDC99 intedace is used to address peripherals which are normally enabled (Figure 6.2-1). 6.3 RING INTERRUPTS NO , RING LINE STILL YES HIGH ? ADDRESS SDs TO DETERMINE RING DEVICE RAISE ME TO ENABLE MODEM/TERMTNAL There are three peripherals that can raise the CR10's ring line; modems, the CR1OKD Keyboard Display, and the RF Modem FIGURE 6.3-1. Servicing of Ring Interrupts configured for synchronous device for communication (RF-SDC). The RF-SDC is 6.4 INTERRUPTS DURING DATA TRANSFER used when the CR10 is installed at a telephone to RF base station. lnstruction 96 is used for on-line data transfer to peripherals (Section 4.1). Each peripheral When the Ring line is raised, the processor is interrupted, and the CR10 determines which peripheral raised the Ring line through a process of elimination (Figure 6.3-1). The CR10 raises the CLI(HS line forcing all SDs to drop the ring line. lf the ring line is still high the peripheral is a modem, and the ME line is raised. lf the ring line is low the CR10 addresses the Keyboard Display connected to the CR10 requires an Instruction 96 with the appropriate parameter. lf the CR10 is already communicating on the 9-pin connector when lnstruction 96 is executed, the instruction puts the output request in a "queue" and program execution continues. As the 9-pin connector becomes available, each device in the queue will get its turn untilthe queue is empty. and RF-SDC to determine which device to service. (Section 6.6) lnstruction 96 is aborted if a modem raises the Ring line. Data transfer to an addressed peripheral is After the CR10 has determined which peripheral raised the Ring line, the hierarchy is as follows: A modem which raises the Ring line will interrupt and gain control of the CR10. The one exception is that a modem cannot interrupt an active RFSDC. A ring from a modem aborts data transfer to pin-enabled and addressed peripherals. The CR1OKD raises the ring line whenever a key is pressed. The CR1OKD will not be serviced when the modem or RF-SDC is being serviced. aborted if the ring line is raised by a CR1OKD or RF Modem configured as a synchronous device. Transfer of data is not resumed untilthe next time Instruction 96 is executed and the datalogger has exited telecommunications. The *8 Mode is used to manually initiate data transfer from Final Storage to a peripheral. An abort flag is set if any key on the CR1OKD or terminal is pressed during the transfer. Data transfer is stopped and the memory location displayed when the flag is set. During *8 data The ring from the CR1OKD and RF-SDC is blocked when the SDE line is high, preventing it lrom interrupting data transfer to a pin-enabled print device. transfer the abort flag is checked as follows: 1. Comma delineated ASCII - after every 32 characters. 2. Printable ASCII - after every line. 3. Binary - after every 256 Final Storage locations. 4. Tape - after every block (512 Final Storage locations).