Let’s take a detailed look at the RAM array word.
	The most significant four bits in a RAM array entry are used to control the RAS or the chip select signal. The next four bits are used to control the CAS or the byte select signal.
	The next two bytes are primarily used to control the general purpose lines. These bytes include two additional functions. One is the wait enable bit, WAEN. As mentioned earlier, if the UPM encounters an entry in which the WAEN bit is set, the UPM determines whether the UPWAIT signal is asserted. If the UPWAIT signal is asserted, the UPM halts until the UPWAIT signal negates. The other function is the data latch 3, DLT3.
	The last byte in a RAM array entry is comprised of a set of control bits. The LOOP bit enables looping within the RAM array entries. Two consecutive RAM array entries with the LOOP bit set indicates the beginning and end of a loop. The machine mode register, either MAMR or MBMR, specifies the number of times that the Array Pointer Generator will execute the loop. The fields used to specify this number depends on the access type. For read access, the number is specified in RLFx0_RLFx3. For write access, the number is specified in WLFx0_WLFx3. For refresh access, the number is specified in TLFx0_TLFx3.
	When EXEN is set, the UPM allows exceptions to interrupt the access underway. This event jumps to the RAM array code which defines how you want to terminate the memory cycle before the MPC860 processes the interrupt. Typically, the exception RAM words are used to ensure that all of the bus signals are released, avoiding possible bus contention while the interrupt is being serviced.
	AMX0 and AMX1 control the address multiplexing, or the switching from row to column addresses. The next address bit, NA, controls when to assert the next address during a burst. The UTA bit controls the assertion of the TA* signal. The turn-on disable time bit (TODT) controls the disable timer mechanism, that is, the RAS precharge timer. Finally, setting the LAST bit to 1 indicates that this entry is the last UPM service requested.