T83C5101 查看數據表（PDF） - Temic Semiconductors
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T83C5101 Datasheet PDF : 52 Pages
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T87C5101
T83C5101/02
6. Low Pin Count specificities
The T8xC5101/02 family is not able to perform any external memory access, such as a code fetch, a look-up table
access (using MOVC) or a data access (using MOVX) because traditional Port 0 and Port 2 are not implemented
anymore. It should be noted that 2 bits of a new port 4 are available, but they are pure user outputs. On the 28
pin package, there is also a set of 4 extra I/Os, which cannot be used for external access.
This inability to perform external memory accesses has the following consequences:
q Port 0 SFR doesn’t exist any more
q Port 2 SFR doesn’t exist any more
q Port 4 has six bits defined among which two are pure outputs for LED driving.
q Security level 4 is no longer applicable
q Code memory addresses is limited to 4000h. Accessing to any address above 3FFFh will return indeterminate
value. Jumps, subroutine Calls, MOVC instructions should be limited to a maximum address range of 3FFFh
to avoid any error.
q External data memory addresses is limited to 100h. Writing to any address above FFh will have no effect.
Reading any address above FFh will return indeterminate value. To avoid any mistake, MOVX address should
be limited to a maximum address range of FFh.
q In Rx devices, the user could disable the XRAM (for example, if he had shared resource at the corresponding
address range). As no external access is possible with the T83/87C510x, it makes no sense to be able to disable
accesses to XRAM. Nevertheless, access to AUXR bit 1 will cause no error and any write to this bit will have
no effect.
q As there is no external access, EA, ALE, PSEN, RD and WR signals are not implemented. So, the corresponding
pins or alternate functions are removed.
q As there is no ALE, there is no need for ALE disabling. Nevertheless, access to AUXR bit 0 will cause no
error and any write to this bit will have no effect.
q Compared to the corresponding 16 Kbyte Rx2 device, the TS80C51RB2, the following features are removed:
• Port 0 & 2
• PCA
• Watchdog
• ONCE mode
• Power Off Flag (POF)
6
Rev. E - 29 February 2000
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