Maxim Integrated Ultra-High-Speed Flash Microcontroller - Manual (Page 88)

6-21
Page Mode 1 Data Memory Timing–Pages 1:0 = 00b (One Cycle) (continued)
Figure 6-21, still using a MOVX stretch value = 0, shows the back-to-back MOVX instructions being executed from external program
memory.
Figure 6-22 shows external code memory execution of an external MOVX instruction with stretch value = 4 (MD2:0 = 100b). It has been
assumed, for this example, that a page-miss is required for the MOVX data access. A stretch value = 4 results in the addition of 4
stretch cycles beyond the stretch value = 3. The four stretch cycles are distributed as folllows: two stretch cycles added for address
setup, one stretch cycle added to RD or WR pulse duration, and 1 stretch cycle added for address/data hold. For subsequent stretch
values of 5, 6, or 7, the added stretch cycle increases the RD or WR pulse duration.
Ultra-High-Speed Flash
Microcontroller User’s Guide
SYSCLK
ALE
PSEN
PORT2 LSB LSB LSB
MOVX
MSB
MOVX
LSB
MOVX
MSB
MOVX
#1
MOVX
#2
MOVX #1
DATA ACCESS
(PAGE MISS)
MOVX #2
DATA ACCESS
(PAGE MISS)
INST
(PAGE MISS)
INST
(PAGE MISS)
INSTRUCTIONS
MOVX
LSB
MOVX
DATA
MOVX
DATA
MSB MSB LSB LSB LSB LSB LSB LSB LSB
PORT0
WR/RD
= STRETCH CYCLES
SYSCLK
ALE
PSEN
PORT2
PORT0
MOVX INST
WR/RD
Figure 6-22. One-Cycle Page Mode 1: MOVX (Nine Cycles) External Code Execution
Figure 6-21. One-Cycle Page Mode 1: MOVX (Two Cycles)—MOVX (Two Cycles) External Code Execution
Maxim Integrated