8XC196Kx, Jx, CA USER’S MANUAL

Table 16-10. Timing Mnemonics (Continued)

16.9 AUTO PROGRAMMING MODE

The auto programming mode is a low-cost programming alternative. Using this programming mode, the device programs itself with data from an external EPROM (external locations 4000H and above). A bank switching mechanism supplied by P1.2 and P1.1 supports auto programming of devices with more than 16 Kbytes of internal memory.

16.9.1 Auto Programming Circuit and Memory Map

Figure 16-12 shows the recommended circuit for an 8XC196Kx device and Table 16-11 shows the memory map for auto programming mode. Auto programming is specified for a crystal frequency of 6 to 8 MHz for commercial devices and 6 to 10 MHz for automotive devices. At 8 MHz, use a 27(C)512 EPROM with tACC = 250 ns and tOE = 100 ns or faster specifications. At 10 MHz, use a 27(C)512 EPROM with tACC = 245 ns and tOE = 100 ns or faster specifications.

Tie the BUSWIDTH pin low to configure an 8-bit data bus. Connect P1.1 and P1.2 as shown to generate the high-order bits of the external EPROM address. Connect P0.7:4 to VSS and VCC to select auto programming (1100B = 0CH). PACT# and PVER are status outputs, buffered by the 74HC14s. They drive LEDs that indicate programming active (PACT#) and programming verification (PVER). Connect all unused inputs to ground (VSS) and leave unused outputs floating. READY and NMI are active; connect them as indicated.

NOTE

All external EPROM addresses specified in this section are given for the circuit in Figure 16-12. If you choose a different circuit, you must adjust the addresses accordingly.

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PROGRAMMING THE NONVOLATILE MEMORY

Figure 16-12. Auto Programming Circuit for 8XC196Kx Devices

NOTE

The 8XC196CA and Jx devices support only a 16-bit, zero-wait-state bus configuration for auto programming. For these devices, omit the BUSWIDTH, P2.5, and P2.3 connections (the pins are not implemented). For the 8XC196Jx, also omit the NMI connection (the pin is not implemented).

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8XC196Kx, Jx, CA USER’S MANUAL

Table 16-11. Auto Programming Memory Map

16.9.2 Operating Environment

In the auto programming mode, the PCCBs are loaded into the chip configuration registers. Since the device gets programming data through the external bus, the memory device in the programming system must correspond to the default configuration (Figure 16-6 on page 16-19). Auto programming requires an 8-bit bus configuration, so the circuit must tie the BUSWIDTH pin low. The PCCB defaults allow you to use any standard EPROM that satisfies the AC specifications listed in the device datasheet.

The auto programming mode also loads CCB0 into an internal RAM location and checks the lock bits. If either lock bit is programmed, the auto programming routine compares the internal security key to the external security key location. If the verification fails, the device enters an endless internal loop. If the security keys match, the routine continues. The auto programming routine uses the modified quick-pulse algorithm and the pulse width value programmed into the external EPROM (locations 14H and 15H).

16.9.3 Auto Programming Routine

Figure 16-13 illustrates the auto programming routine. This routine checks the security lock bits in CCB0; if either bit is programmed, it compares the internal security key to the external security key locations. If the security keys match, the routine continues; otherwise, the device enters an endless loop.

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PROGRAMMING THE NONVOLATILE MEMORY

Figure 16-13. Auto Programming Routine

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